systematic review process research

Systematic Review

• Library Help
• What is a Systematic Review (SR)?

Steps of a Systematic Review

• Framing a Research Question
• Developing a Search Strategy
• Searching the Literature
• Managing the Process
• Meta-analysis
• Publishing your Systematic Review

Forms and templates

Image: David Parmenter's Shop

• PICO Template
• Inclusion/Exclusion Criteria
• Database Search Log
• Review Matrix
• Cochrane Tool for Assessing Risk of Bias in Included Studies

   • PRISMA Flow Diagram  - Record the numbers of retrieved references and included/excluded studies. You can use the Create Flow Diagram tool to automate the process.

   •  PRISMA Checklist - Checklist of items to include when reporting a systematic review or meta-analysis

PRISMA 2020 and PRISMA-S: Common Questions on Tracking Records and the Flow Diagram

• PROSPERO Template
• Manuscript Template
• Steps of SR (text)
• Steps of SR (visual)
• Steps of SR (PIECES)

Adapted from  A Guide to Conducting Systematic Reviews: Steps in a Systematic Review by Cornell University Library

Source: Cochrane Consumers and Communications  (infographics are free to use and licensed under Creative Commons )

Check the following visual resources titled " What Are Systematic Reviews?"

• Video  with closed captions available
• Animated Storyboard

• << Previous: What is a Systematic Review (SR)?
• Next: Framing a Research Question >>
• Last Updated: Aug 26, 2024 12:37 PM
• URL: https://lib.guides.umd.edu/SR

Have a language expert improve your writing

Run a free plagiarism check in 10 minutes, generate accurate citations for free.

• Knowledge Base

Methodology

• Systematic Review | Definition, Example, & Guide

Systematic Review | Definition, Example & Guide

Published on June 15, 2022 by Shaun Turney . Revised on November 20, 2023.

A systematic review is a type of review that uses repeatable methods to find, select, and synthesize all available evidence. It answers a clearly formulated research question and explicitly states the methods used to arrive at the answer.

They answered the question “What is the effectiveness of probiotics in reducing eczema symptoms and improving quality of life in patients with eczema?”

In this context, a probiotic is a health product that contains live microorganisms and is taken by mouth. Eczema is a common skin condition that causes red, itchy skin.

Table of contents

What is a systematic review, systematic review vs. meta-analysis, systematic review vs. literature review, systematic review vs. scoping review, when to conduct a systematic review, pros and cons of systematic reviews, step-by-step example of a systematic review, other interesting articles, frequently asked questions about systematic reviews.

A review is an overview of the research that’s already been completed on a topic.

What makes a systematic review different from other types of reviews is that the research methods are designed to reduce bias . The methods are repeatable, and the approach is formal and systematic:

• Formulate a research question
• Develop a protocol
• Search for all relevant studies
• Apply the selection criteria
• Extract the data
• Synthesize the data
• Write and publish a report

Although multiple sets of guidelines exist, the Cochrane Handbook for Systematic Reviews is among the most widely used. It provides detailed guidelines on how to complete each step of the systematic review process.

Systematic reviews are most commonly used in medical and public health research, but they can also be found in other disciplines.

Systematic reviews typically answer their research question by synthesizing all available evidence and evaluating the quality of the evidence. Synthesizing means bringing together different information to tell a single, cohesive story. The synthesis can be narrative ( qualitative ), quantitative , or both.

Here's why students love Scribbr's proofreading services

Discover proofreading & editing

Systematic reviews often quantitatively synthesize the evidence using a meta-analysis . A meta-analysis is a statistical analysis, not a type of review.

A meta-analysis is a technique to synthesize results from multiple studies. It’s a statistical analysis that combines the results of two or more studies, usually to estimate an effect size .

A literature review is a type of review that uses a less systematic and formal approach than a systematic review. Typically, an expert in a topic will qualitatively summarize and evaluate previous work, without using a formal, explicit method.

Although literature reviews are often less time-consuming and can be insightful or helpful, they have a higher risk of bias and are less transparent than systematic reviews.

Similar to a systematic review, a scoping review is a type of review that tries to minimize bias by using transparent and repeatable methods.

However, a scoping review isn’t a type of systematic review. The most important difference is the goal: rather than answering a specific question, a scoping review explores a topic. The researcher tries to identify the main concepts, theories, and evidence, as well as gaps in the current research.

Sometimes scoping reviews are an exploratory preparation step for a systematic review, and sometimes they are a standalone project.

A systematic review is a good choice of review if you want to answer a question about the effectiveness of an intervention , such as a medical treatment.

To conduct a systematic review, you’ll need the following:

• A precise question , usually about the effectiveness of an intervention. The question needs to be about a topic that’s previously been studied by multiple researchers. If there’s no previous research, there’s nothing to review.
• If you’re doing a systematic review on your own (e.g., for a research paper or thesis ), you should take appropriate measures to ensure the validity and reliability of your research.
• Access to databases and journal archives. Often, your educational institution provides you with access.
• Time. A professional systematic review is a time-consuming process: it will take the lead author about six months of full-time work. If you’re a student, you should narrow the scope of your systematic review and stick to a tight schedule.
• Bibliographic, word-processing, spreadsheet, and statistical software . For example, you could use EndNote, Microsoft Word, Excel, and SPSS.

A systematic review has many pros .

• They minimize research bias by considering all available evidence and evaluating each study for bias.
• Their methods are transparent , so they can be scrutinized by others.
• They’re thorough : they summarize all available evidence.
• They can be replicated and updated by others.

Systematic reviews also have a few cons .

• They’re time-consuming .
• They’re narrow in scope : they only answer the precise research question.

The 7 steps for conducting a systematic review are explained with an example.

Step 1: Formulate a research question

Formulating the research question is probably the most important step of a systematic review. A clear research question will:

• Allow you to more effectively communicate your research to other researchers and practitioners
• Guide your decisions as you plan and conduct your systematic review

A good research question for a systematic review has four components, which you can remember with the acronym PICO :

• Population(s) or problem(s)
• Intervention(s)
• Comparison(s)

You can rearrange these four components to write your research question:

• What is the effectiveness of I versus C for O in P ?

Sometimes, you may want to include a fifth component, the type of study design . In this case, the acronym is PICOT .

• Type of study design(s)
• The population of patients with eczema
• The intervention of probiotics
• In comparison to no treatment, placebo , or non-probiotic treatment
• The outcome of changes in participant-, parent-, and doctor-rated symptoms of eczema and quality of life
• Randomized control trials, a type of study design

Their research question was:

• What is the effectiveness of probiotics versus no treatment, a placebo, or a non-probiotic treatment for reducing eczema symptoms and improving quality of life in patients with eczema?

Step 2: Develop a protocol

A protocol is a document that contains your research plan for the systematic review. This is an important step because having a plan allows you to work more efficiently and reduces bias.

Your protocol should include the following components:

• Background information : Provide the context of the research question, including why it’s important.
• Research objective (s) : Rephrase your research question as an objective.
• Selection criteria: State how you’ll decide which studies to include or exclude from your review.
• Search strategy: Discuss your plan for finding studies.
• Analysis: Explain what information you’ll collect from the studies and how you’ll synthesize the data.

If you’re a professional seeking to publish your review, it’s a good idea to bring together an advisory committee . This is a group of about six people who have experience in the topic you’re researching. They can help you make decisions about your protocol.

It’s highly recommended to register your protocol. Registering your protocol means submitting it to a database such as PROSPERO or ClinicalTrials.gov .

Step 3: Search for all relevant studies

Searching for relevant studies is the most time-consuming step of a systematic review.

To reduce bias, it’s important to search for relevant studies very thoroughly. Your strategy will depend on your field and your research question, but sources generally fall into these four categories:

• Databases: Search multiple databases of peer-reviewed literature, such as PubMed or Scopus . Think carefully about how to phrase your search terms and include multiple synonyms of each word. Use Boolean operators if relevant.
• Handsearching: In addition to searching the primary sources using databases, you’ll also need to search manually. One strategy is to scan relevant journals or conference proceedings. Another strategy is to scan the reference lists of relevant studies.
• Gray literature: Gray literature includes documents produced by governments, universities, and other institutions that aren’t published by traditional publishers. Graduate student theses are an important type of gray literature, which you can search using the Networked Digital Library of Theses and Dissertations (NDLTD) . In medicine, clinical trial registries are another important type of gray literature.
• Experts: Contact experts in the field to ask if they have unpublished studies that should be included in your review.

At this stage of your review, you won’t read the articles yet. Simply save any potentially relevant citations using bibliographic software, such as Scribbr’s APA or MLA Generator .

• Databases: EMBASE, PsycINFO, AMED, LILACS, and ISI Web of Science
• Handsearch: Conference proceedings and reference lists of articles
• Gray literature: The Cochrane Library, the metaRegister of Controlled Trials, and the Ongoing Skin Trials Register
• Experts: Authors of unpublished registered trials, pharmaceutical companies, and manufacturers of probiotics

Step 4: Apply the selection criteria

Applying the selection criteria is a three-person job. Two of you will independently read the studies and decide which to include in your review based on the selection criteria you established in your protocol . The third person’s job is to break any ties.

To increase inter-rater reliability , ensure that everyone thoroughly understands the selection criteria before you begin.

If you’re writing a systematic review as a student for an assignment, you might not have a team. In this case, you’ll have to apply the selection criteria on your own; you can mention this as a limitation in your paper’s discussion.

You should apply the selection criteria in two phases:

• Based on the titles and abstracts : Decide whether each article potentially meets the selection criteria based on the information provided in the abstracts.
• Based on the full texts: Download the articles that weren’t excluded during the first phase. If an article isn’t available online or through your library, you may need to contact the authors to ask for a copy. Read the articles and decide which articles meet the selection criteria.

It’s very important to keep a meticulous record of why you included or excluded each article. When the selection process is complete, you can summarize what you did using a PRISMA flow diagram .

Next, Boyle and colleagues found the full texts for each of the remaining studies. Boyle and Tang read through the articles to decide if any more studies needed to be excluded based on the selection criteria.

When Boyle and Tang disagreed about whether a study should be excluded, they discussed it with Varigos until the three researchers came to an agreement.

Step 5: Extract the data

Extracting the data means collecting information from the selected studies in a systematic way. There are two types of information you need to collect from each study:

• Information about the study’s methods and results . The exact information will depend on your research question, but it might include the year, study design , sample size, context, research findings , and conclusions. If any data are missing, you’ll need to contact the study’s authors.
• Your judgment of the quality of the evidence, including risk of bias .

You should collect this information using forms. You can find sample forms in The Registry of Methods and Tools for Evidence-Informed Decision Making and the Grading of Recommendations, Assessment, Development and Evaluations Working Group .

Extracting the data is also a three-person job. Two people should do this step independently, and the third person will resolve any disagreements.

They also collected data about possible sources of bias, such as how the study participants were randomized into the control and treatment groups.

Step 6: Synthesize the data

Synthesizing the data means bringing together the information you collected into a single, cohesive story. There are two main approaches to synthesizing the data:

• Narrative ( qualitative ): Summarize the information in words. You’ll need to discuss the studies and assess their overall quality.
• Quantitative : Use statistical methods to summarize and compare data from different studies. The most common quantitative approach is a meta-analysis , which allows you to combine results from multiple studies into a summary result.

Generally, you should use both approaches together whenever possible. If you don’t have enough data, or the data from different studies aren’t comparable, then you can take just a narrative approach. However, you should justify why a quantitative approach wasn’t possible.

Boyle and colleagues also divided the studies into subgroups, such as studies about babies, children, and adults, and analyzed the effect sizes within each group.

Step 7: Write and publish a report

The purpose of writing a systematic review article is to share the answer to your research question and explain how you arrived at this answer.

Your article should include the following sections:

• Abstract : A summary of the review
• Introduction : Including the rationale and objectives
• Methods : Including the selection criteria, search method, data extraction method, and synthesis method
• Results : Including results of the search and selection process, study characteristics, risk of bias in the studies, and synthesis results
• Discussion : Including interpretation of the results and limitations of the review
• Conclusion : The answer to your research question and implications for practice, policy, or research

To verify that your report includes everything it needs, you can use the PRISMA checklist .

Once your report is written, you can publish it in a systematic review database, such as the Cochrane Database of Systematic Reviews , and/or in a peer-reviewed journal.

In their report, Boyle and colleagues concluded that probiotics cannot be recommended for reducing eczema symptoms or improving quality of life in patients with eczema. Note Generative AI tools like ChatGPT can be useful at various stages of the writing and research process and can help you to write your systematic review. However, we strongly advise against trying to pass AI-generated text off as your own work.

If you want to know more about statistics , methodology , or research bias , make sure to check out some of our other articles with explanations and examples.

• Student’s  t -distribution
• Normal distribution
• Null and Alternative Hypotheses
• Chi square tests
• Confidence interval
• Quartiles & Quantiles
• Cluster sampling
• Stratified sampling
• Data cleansing
• Reproducibility vs Replicability
• Peer review
• Prospective cohort study

Research bias

• Implicit bias
• Cognitive bias
• Placebo effect
• Hawthorne effect
• Hindsight bias
• Affect heuristic
• Social desirability bias

A literature review is a survey of scholarly sources (such as books, journal articles, and theses) related to a specific topic or research question .

It is often written as part of a thesis, dissertation , or research paper , in order to situate your work in relation to existing knowledge.

A literature review is a survey of credible sources on a topic, often used in dissertations , theses, and research papers . Literature reviews give an overview of knowledge on a subject, helping you identify relevant theories and methods, as well as gaps in existing research. Literature reviews are set up similarly to other  academic texts , with an introduction , a main body, and a conclusion .

An  annotated bibliography is a list of  source references that has a short description (called an annotation ) for each of the sources. It is often assigned as part of the research process for a  paper .  

A systematic review is secondary research because it uses existing research. You don’t collect new data yourself.

Cite this Scribbr article

If you want to cite this source, you can copy and paste the citation or click the “Cite this Scribbr article” button to automatically add the citation to our free Citation Generator.

Turney, S. (2023, November 20). Systematic Review | Definition, Example & Guide. Scribbr. Retrieved August 26, 2024, from https://www.scribbr.com/methodology/systematic-review/

Is this article helpful?

Shaun Turney

Other students also liked, how to write a literature review | guide, examples, & templates, how to write a research proposal | examples & templates, what is critical thinking | definition & examples, get unlimited documents corrected.

✔ Free APA citation check included ✔ Unlimited document corrections ✔ Specialized in correcting academic texts

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings
• My Bibliography
• Collections
• Citation manager

Save citation to file

Email citation, add to collections.

• Create a new collection
• Add to an existing collection

Add to My Bibliography

Your saved search, create a file for external citation management software, your rss feed.

• Search in PubMed
• Search in NLM Catalog
• Add to Search

How to Do a Systematic Review: A Best Practice Guide for Conducting and Reporting Narrative Reviews, Meta-Analyses, and Meta-Syntheses

Affiliations.

• 1 Behavioural Science Centre, Stirling Management School, University of Stirling, Stirling FK9 4LA, United Kingdom; email: [email protected].
• 2 Department of Psychological and Behavioural Science, London School of Economics and Political Science, London WC2A 2AE, United Kingdom.
• 3 Department of Statistics, Northwestern University, Evanston, Illinois 60208, USA; email: [email protected].
• PMID: 30089228
• DOI: 10.1146/annurev-psych-010418-102803

Systematic reviews are characterized by a methodical and replicable methodology and presentation. They involve a comprehensive search to locate all relevant published and unpublished work on a subject; a systematic integration of search results; and a critique of the extent, nature, and quality of evidence in relation to a particular research question. The best reviews synthesize studies to draw broad theoretical conclusions about what a literature means, linking theory to evidence and evidence to theory. This guide describes how to plan, conduct, organize, and present a systematic review of quantitative (meta-analysis) or qualitative (narrative review, meta-synthesis) information. We outline core standards and principles and describe commonly encountered problems. Although this guide targets psychological scientists, its high level of abstraction makes it potentially relevant to any subject area or discipline. We argue that systematic reviews are a key methodology for clarifying whether and how research findings replicate and for explaining possible inconsistencies, and we call for researchers to conduct systematic reviews to help elucidate whether there is a replication crisis.

Keywords: evidence; guide; meta-analysis; meta-synthesis; narrative; systematic review; theory.

PubMed Disclaimer

Similar articles

• The future of Cochrane Neonatal. Soll RF, Ovelman C, McGuire W. Soll RF, et al. Early Hum Dev. 2020 Nov;150:105191. doi: 10.1016/j.earlhumdev.2020.105191. Epub 2020 Sep 12. Early Hum Dev. 2020. PMID: 33036834
• Summarizing systematic reviews: methodological development, conduct and reporting of an umbrella review approach. Aromataris E, Fernandez R, Godfrey CM, Holly C, Khalil H, Tungpunkom P. Aromataris E, et al. Int J Evid Based Healthc. 2015 Sep;13(3):132-40. doi: 10.1097/XEB.0000000000000055. Int J Evid Based Healthc. 2015. PMID: 26360830
• RAMESES publication standards: meta-narrative reviews. Wong G, Greenhalgh T, Westhorp G, Buckingham J, Pawson R. Wong G, et al. BMC Med. 2013 Jan 29;11:20. doi: 10.1186/1741-7015-11-20. BMC Med. 2013. PMID: 23360661 Free PMC article.
• A Primer on Systematic Reviews and Meta-Analyses. Nguyen NH, Singh S. Nguyen NH, et al. Semin Liver Dis. 2018 May;38(2):103-111. doi: 10.1055/s-0038-1655776. Epub 2018 Jun 5. Semin Liver Dis. 2018. PMID: 29871017 Review.
• Publication Bias and Nonreporting Found in Majority of Systematic Reviews and Meta-analyses in Anesthesiology Journals. Hedin RJ, Umberham BA, Detweiler BN, Kollmorgen L, Vassar M. Hedin RJ, et al. Anesth Analg. 2016 Oct;123(4):1018-25. doi: 10.1213/ANE.0000000000001452. Anesth Analg. 2016. PMID: 27537925 Review.
• Bridging disciplines-key to success when implementing planetary health in medical training curricula. Malmqvist E, Oudin A. Malmqvist E, et al. Front Public Health. 2024 Aug 6;12:1454729. doi: 10.3389/fpubh.2024.1454729. eCollection 2024. Front Public Health. 2024. PMID: 39165783 Free PMC article. Review.
• Strength of evidence for five happiness strategies. Puterman E, Zieff G, Stoner L. Puterman E, et al. Nat Hum Behav. 2024 Aug 12. doi: 10.1038/s41562-024-01954-0. Online ahead of print. Nat Hum Behav. 2024. PMID: 39134738 No abstract available.
• Nursing Education During the SARS-COVID-19 Pandemic: The Implementation of Information and Communication Technologies (ICT). Soto-Luffi O, Villegas C, Viscardi S, Ulloa-Inostroza EM. Soto-Luffi O, et al. Med Sci Educ. 2024 May 9;34(4):949-959. doi: 10.1007/s40670-024-02056-2. eCollection 2024 Aug. Med Sci Educ. 2024. PMID: 39099870 Review.
• Surveillance of Occupational Exposure to Volatile Organic Compounds at Gas Stations: A Scoping Review Protocol. Mendes TMC, Soares JP, Salvador PTCO, Castro JL. Mendes TMC, et al. Int J Environ Res Public Health. 2024 Apr 23;21(5):518. doi: 10.3390/ijerph21050518. Int J Environ Res Public Health. 2024. PMID: 38791733 Free PMC article. Review.
• Association between poor sleep and mental health issues in Indigenous communities across the globe: a systematic review. Fernandez DR, Lee R, Tran N, Jabran DS, King S, McDaid L. Fernandez DR, et al. Sleep Adv. 2024 May 2;5(1):zpae028. doi: 10.1093/sleepadvances/zpae028. eCollection 2024. Sleep Adv. 2024. PMID: 38721053 Free PMC article.
• Search in MeSH

LinkOut - more resources

Full text sources.

• Ingenta plc
• Ovid Technologies, Inc.

Other Literature Sources

• scite Smart Citations

Miscellaneous

• NCI CPTAC Assay Portal
• Citation Manager

NCBI Literature Resources

MeSH PMC Bookshelf Disclaimer

The PubMed wordmark and PubMed logo are registered trademarks of the U.S. Department of Health and Human Services (HHS). Unauthorized use of these marks is strictly prohibited.

Introduction to Systematic Reviews

In this guide.

• Introduction
• Types of Reviews
• Systematic Review Process
• Protocols & Guidelines
• Data Extraction and Screening
• Resources & Tools

The Systematic Review Process

Adapted from  "The Systematic Review Process" Yale Medical Library and Tsafnat et al. (2014).

Tsafnat, G., Glasziou, P., Choong, M. K., Dunn, A., Galgani, F., & Coiera, E. (2014). Systematic review automation technologies.  Systematic reviews ,  3 (1), 74. DOI:  https://doi.org/10.1186/2046-4053-3-74 

• << Previous: Types of Reviews
• Next: Protocols & Guidelines >>
• Last Updated: Jul 31, 2024 1:44 PM
• URL: https://laneguides.stanford.edu/systematicreviews

Have a language expert improve your writing

Run a free plagiarism check in 10 minutes, automatically generate references for free.

• Knowledge Base
• Methodology
• Systematic Review | Definition, Examples & Guide

Systematic Review | Definition, Examples & Guide

Published on 15 June 2022 by Shaun Turney . Revised on 18 July 2024.

A systematic review is a type of review that uses repeatable methods to find, select, and synthesise all available evidence. It answers a clearly formulated research question and explicitly states the methods used to arrive at the answer.

They answered the question ‘What is the effectiveness of probiotics in reducing eczema symptoms and improving quality of life in patients with eczema?’

In this context, a probiotic is a health product that contains live microorganisms and is taken by mouth. Eczema is a common skin condition that causes red, itchy skin.

Table of contents

What is a systematic review, systematic review vs meta-analysis, systematic review vs literature review, systematic review vs scoping review, when to conduct a systematic review, pros and cons of systematic reviews, step-by-step example of a systematic review, frequently asked questions about systematic reviews.

A review is an overview of the research that’s already been completed on a topic.

What makes a systematic review different from other types of reviews is that the research methods are designed to reduce research bias . The methods are repeatable , and the approach is formal and systematic:

• Formulate a research question
• Develop a protocol
• Search for all relevant studies
• Apply the selection criteria
• Extract the data
• Synthesise the data
• Write and publish a report

Although multiple sets of guidelines exist, the Cochrane Handbook for Systematic Reviews is among the most widely used. It provides detailed guidelines on how to complete each step of the systematic review process.

Systematic reviews are most commonly used in medical and public health research, but they can also be found in other disciplines.

Systematic reviews typically answer their research question by synthesising all available evidence and evaluating the quality of the evidence. Synthesising means bringing together different information to tell a single, cohesive story. The synthesis can be narrative ( qualitative ), quantitative , or both.

Prevent plagiarism, run a free check.

Systematic reviews often quantitatively synthesise the evidence using a meta-analysis . A meta-analysis is a statistical analysis, not a type of review.

A meta-analysis is a technique to synthesise results from multiple studies. It’s a statistical analysis that combines the results of two or more studies, usually to estimate an effect size .

A literature review is a type of review that uses a less systematic and formal approach than a systematic review. Typically, an expert in a topic will qualitatively summarise and evaluate previous work, without using a formal, explicit method.

Although literature reviews are often less time-consuming and can be insightful or helpful, they have a higher risk of bias and are less transparent than systematic reviews.

Similar to a systematic review, a scoping review is a type of review that tries to minimise bias by using transparent and repeatable methods.

However, a scoping review isn’t a type of systematic review. The most important difference is the goal: rather than answering a specific question, a scoping review explores a topic. The researcher tries to identify the main concepts, theories, and evidence, as well as gaps in the current research.

Sometimes scoping reviews are an exploratory preparation step for a systematic review, and sometimes they are a standalone project.

A systematic review is a good choice of review if you want to answer a question about the effectiveness of an intervention , such as a medical treatment.

To conduct a systematic review, you’ll need the following:

• A precise question , usually about the effectiveness of an intervention. The question needs to be about a topic that’s previously been studied by multiple researchers. If there’s no previous research, there’s nothing to review.
• If you’re doing a systematic review on your own (e.g., for a research paper or thesis), you should take appropriate measures to ensure the validity and reliability of your research.
• Access to databases and journal archives. Often, your educational institution provides you with access.
• Time. A professional systematic review is a time-consuming process: it will take the lead author about six months of full-time work. If you’re a student, you should narrow the scope of your systematic review and stick to a tight schedule.
• Bibliographic, word-processing, spreadsheet, and statistical software . For example, you could use EndNote, Microsoft Word, Excel, and SPSS.

A systematic review has many pros .

• They minimise research b ias by considering all available evidence and evaluating each study for bias.
• Their methods are transparent , so they can be scrutinised by others.
• They’re thorough : they summarise all available evidence.
• They can be replicated and updated by others.

Systematic reviews also have a few cons .

• They’re time-consuming .
• They’re narrow in scope : they only answer the precise research question.

The 7 steps for conducting a systematic review are explained with an example.

Step 1: Formulate a research question

Formulating the research question is probably the most important step of a systematic review. A clear research question will:

• Allow you to more effectively communicate your research to other researchers and practitioners
• Guide your decisions as you plan and conduct your systematic review

A good research question for a systematic review has four components, which you can remember with the acronym PICO :

• Population(s) or problem(s)
• Intervention(s)
• Comparison(s)

You can rearrange these four components to write your research question:

• What is the effectiveness of I versus C for O in P ?

Sometimes, you may want to include a fourth component, the type of study design . In this case, the acronym is PICOT .

• Type of study design(s)
• The population of patients with eczema
• The intervention of probiotics
• In comparison to no treatment, placebo , or non-probiotic treatment
• The outcome of changes in participant-, parent-, and doctor-rated symptoms of eczema and quality of life
• Randomised control trials, a type of study design

Their research question was:

• What is the effectiveness of probiotics versus no treatment, a placebo, or a non-probiotic treatment for reducing eczema symptoms and improving quality of life in patients with eczema?

Step 2: Develop a protocol

A protocol is a document that contains your research plan for the systematic review. This is an important step because having a plan allows you to work more efficiently and reduces bias.

Your protocol should include the following components:

• Background information : Provide the context of the research question, including why it’s important.
• Research objective(s) : Rephrase your research question as an objective.
• Selection criteria: State how you’ll decide which studies to include or exclude from your review.
• Search strategy: Discuss your plan for finding studies.
• Analysis: Explain what information you’ll collect from the studies and how you’ll synthesise the data.

If you’re a professional seeking to publish your review, it’s a good idea to bring together an advisory committee . This is a group of about six people who have experience in the topic you’re researching. They can help you make decisions about your protocol.

It’s highly recommended to register your protocol. Registering your protocol means submitting it to a database such as PROSPERO or ClinicalTrials.gov .

Step 3: Search for all relevant studies

Searching for relevant studies is the most time-consuming step of a systematic review.

To reduce bias, it’s important to search for relevant studies very thoroughly. Your strategy will depend on your field and your research question, but sources generally fall into these four categories:

• Databases: Search multiple databases of peer-reviewed literature, such as PubMed or Scopus . Think carefully about how to phrase your search terms and include multiple synonyms of each word. Use Boolean operators if relevant.
• Handsearching: In addition to searching the primary sources using databases, you’ll also need to search manually. One strategy is to scan relevant journals or conference proceedings. Another strategy is to scan the reference lists of relevant studies.
• Grey literature: Grey literature includes documents produced by governments, universities, and other institutions that aren’t published by traditional publishers. Graduate student theses are an important type of grey literature, which you can search using the Networked Digital Library of Theses and Dissertations (NDLTD) . In medicine, clinical trial registries are another important type of grey literature.
• Experts: Contact experts in the field to ask if they have unpublished studies that should be included in your review.

At this stage of your review, you won’t read the articles yet. Simply save any potentially relevant citations using bibliographic software, such as Scribbr’s APA or MLA Generator .

• Databases: EMBASE, PsycINFO, AMED, LILACS, and ISI Web of Science
• Handsearch: Conference proceedings and reference lists of articles
• Grey literature: The Cochrane Library, the metaRegister of Controlled Trials, and the Ongoing Skin Trials Register
• Experts: Authors of unpublished registered trials, pharmaceutical companies, and manufacturers of probiotics

Step 4: Apply the selection criteria

Applying the selection criteria is a three-person job. Two of you will independently read the studies and decide which to include in your review based on the selection criteria you established in your protocol . The third person’s job is to break any ties.

To increase inter-rater reliability , ensure that everyone thoroughly understands the selection criteria before you begin.

If you’re writing a systematic review as a student for an assignment, you might not have a team. In this case, you’ll have to apply the selection criteria on your own; you can mention this as a limitation in your paper’s discussion.

You should apply the selection criteria in two phases:

• Based on the titles and abstracts : Decide whether each article potentially meets the selection criteria based on the information provided in the abstracts.
• Based on the full texts: Download the articles that weren’t excluded during the first phase. If an article isn’t available online or through your library, you may need to contact the authors to ask for a copy. Read the articles and decide which articles meet the selection criteria.

It’s very important to keep a meticulous record of why you included or excluded each article. When the selection process is complete, you can summarise what you did using a PRISMA flow diagram .

Next, Boyle and colleagues found the full texts for each of the remaining studies. Boyle and Tang read through the articles to decide if any more studies needed to be excluded based on the selection criteria.

When Boyle and Tang disagreed about whether a study should be excluded, they discussed it with Varigos until the three researchers came to an agreement.

Step 5: Extract the data

Extracting the data means collecting information from the selected studies in a systematic way. There are two types of information you need to collect from each study:

• Information about the study’s methods and results . The exact information will depend on your research question, but it might include the year, study design , sample size, context, research findings , and conclusions. If any data are missing, you’ll need to contact the study’s authors.
• Your judgement of the quality of the evidence, including risk of bias .

You should collect this information using forms. You can find sample forms in The Registry of Methods and Tools for Evidence-Informed Decision Making and the Grading of Recommendations, Assessment, Development and Evaluations Working Group .

Extracting the data is also a three-person job. Two people should do this step independently, and the third person will resolve any disagreements.

They also collected data about possible sources of bias, such as how the study participants were randomised into the control and treatment groups.

Step 6: Synthesise the data

Synthesising the data means bringing together the information you collected into a single, cohesive story. There are two main approaches to synthesising the data:

• Narrative ( qualitative ): Summarise the information in words. You’ll need to discuss the studies and assess their overall quality.
• Quantitative : Use statistical methods to summarise and compare data from different studies. The most common quantitative approach is a meta-analysis , which allows you to combine results from multiple studies into a summary result.

Generally, you should use both approaches together whenever possible. If you don’t have enough data, or the data from different studies aren’t comparable, then you can take just a narrative approach. However, you should justify why a quantitative approach wasn’t possible.

Boyle and colleagues also divided the studies into subgroups, such as studies about babies, children, and adults, and analysed the effect sizes within each group.

Step 7: Write and publish a report

The purpose of writing a systematic review article is to share the answer to your research question and explain how you arrived at this answer.

Your article should include the following sections:

• Abstract : A summary of the review
• Introduction : Including the rationale and objectives
• Methods : Including the selection criteria, search method, data extraction method, and synthesis method
• Results : Including results of the search and selection process, study characteristics, risk of bias in the studies, and synthesis results
• Discussion : Including interpretation of the results and limitations of the review
• Conclusion : The answer to your research question and implications for practice, policy, or research

To verify that your report includes everything it needs, you can use the PRISMA checklist .

Once your report is written, you can publish it in a systematic review database, such as the Cochrane Database of Systematic Reviews , and/or in a peer-reviewed journal.

A systematic review is secondary research because it uses existing research. You don’t collect new data yourself.

A literature review is a survey of scholarly sources (such as books, journal articles, and theses) related to a specific topic or research question .

It is often written as part of a dissertation , thesis, research paper , or proposal .

There are several reasons to conduct a literature review at the beginning of a research project:

• To familiarise yourself with the current state of knowledge on your topic
• To ensure that you’re not just repeating what others have already done
• To identify gaps in knowledge and unresolved problems that your research can address
• To develop your theoretical framework and methodology
• To provide an overview of the key findings and debates on the topic

Writing the literature review shows your reader how your work relates to existing research and what new insights it will contribute.

Cite this Scribbr article

If you want to cite this source, you can copy and paste the citation or click the ‘Cite this Scribbr article’ button to automatically add the citation to our free Reference Generator.

Turney, S. (2024, July 17). Systematic Review | Definition, Examples & Guide. Scribbr. Retrieved 26 August 2024, from https://www.scribbr.co.uk/research-methods/systematic-reviews/

Is this article helpful?

Shaun Turney

Other students also liked, what is a literature review | guide, template, & examples, exploratory research | definition, guide, & examples, what is peer review | types & examples.

• A-Z Publications

Annual Review of Psychology

Volume 70, 2019, review article, how to do a systematic review: a best practice guide for conducting and reporting narrative reviews, meta-analyses, and meta-syntheses.

• Andy P. Siddaway 1 , Alex M. Wood 2 , and Larry V. Hedges 3
• View Affiliations Hide Affiliations Affiliations: 1 Behavioural Science Centre, Stirling Management School, University of Stirling, Stirling FK9 4LA, United Kingdom; email: [email protected] 2 Department of Psychological and Behavioural Science, London School of Economics and Political Science, London WC2A 2AE, United Kingdom 3 Department of Statistics, Northwestern University, Evanston, Illinois 60208, USA; email: [email protected]
• Vol. 70:747-770 (Volume publication date January 2019) https://doi.org/10.1146/annurev-psych-010418-102803
• First published as a Review in Advance on August 08, 2018
• Copyright © 2019 by Annual Reviews. All rights reserved

Systematic reviews are characterized by a methodical and replicable methodology and presentation. They involve a comprehensive search to locate all relevant published and unpublished work on a subject; a systematic integration of search results; and a critique of the extent, nature, and quality of evidence in relation to a particular research question. The best reviews synthesize studies to draw broad theoretical conclusions about what a literature means, linking theory to evidence and evidence to theory. This guide describes how to plan, conduct, organize, and present a systematic review of quantitative (meta-analysis) or qualitative (narrative review, meta-synthesis) information. We outline core standards and principles and describe commonly encountered problems. Although this guide targets psychological scientists, its high level of abstraction makes it potentially relevant to any subject area or discipline. We argue that systematic reviews are a key methodology for clarifying whether and how research findings replicate and for explaining possible inconsistencies, and we call for researchers to conduct systematic reviews to help elucidate whether there is a replication crisis.

Article metrics loading...

Full text loading...

Literature Cited

• APA Publ. Commun. Board Work. Group J. Artic. Rep. Stand. 2008 . Reporting standards for research in psychology: Why do we need them? What might they be?. Am. Psychol . 63 : 848– 49 [Google Scholar]
• Baumeister RF 2013 . Writing a literature review. The Portable Mentor: Expert Guide to a Successful Career in Psychology MJ Prinstein, MD Patterson 119– 32 New York: Springer, 2nd ed.. [Google Scholar]
• Baumeister RF , Leary MR 1995 . The need to belong: desire for interpersonal attachments as a fundamental human motivation. Psychol. Bull. 117 : 497– 529 [Google Scholar]
• Baumeister RF , Leary MR 1997 . Writing narrative literature reviews. Rev. Gen. Psychol. 3 : 311– 20 Presents a thorough and thoughtful guide to conducting narrative reviews. [Google Scholar]
• Bem DJ 1995 . Writing a review article for Psychological Bulletin. Psychol . Bull 118 : 172– 77 [Google Scholar]
• Borenstein M , Hedges LV , Higgins JPT , Rothstein HR 2009 . Introduction to Meta-Analysis New York: Wiley Presents a comprehensive introduction to meta-analysis. [Google Scholar]
• Borenstein M , Higgins JPT , Hedges LV , Rothstein HR 2017 . Basics of meta-analysis: I 2 is not an absolute measure of heterogeneity. Res. Synth. Methods 8 : 5– 18 [Google Scholar]
• Braver SL , Thoemmes FJ , Rosenthal R 2014 . Continuously cumulating meta-analysis and replicability. Perspect. Psychol. Sci. 9 : 333– 42 [Google Scholar]
• Bushman BJ 1994 . Vote-counting procedures. The Handbook of Research Synthesis H Cooper, LV Hedges 193– 214 New York: Russell Sage Found. [Google Scholar]
• Cesario J 2014 . Priming, replication, and the hardest science. Perspect. Psychol. Sci. 9 : 40– 48 [Google Scholar]
• Chalmers I 2007 . The lethal consequences of failing to make use of all relevant evidence about the effects of medical treatments: the importance of systematic reviews. Treating Individuals: From Randomised Trials to Personalised Medicine PM Rothwell 37– 58 London: Lancet [Google Scholar]
• Cochrane Collab. 2003 . Glossary Rep., Cochrane Collab. London: http://community.cochrane.org/glossary Presents a comprehensive glossary of terms relevant to systematic reviews. [Google Scholar]
• Cohn LD , Becker BJ 2003 . How meta-analysis increases statistical power. Psychol. Methods 8 : 243– 53 [Google Scholar]
• Cooper HM 2003 . Editorial. Psychol. Bull. 129 : 3– 9 [Google Scholar]
• Cooper HM 2016 . Research Synthesis and Meta-Analysis: A Step-by-Step Approach Thousand Oaks, CA: Sage, 5th ed.. Presents a comprehensive introduction to research synthesis and meta-analysis. [Google Scholar]
• Cooper HM , Hedges LV , Valentine JC 2009 . The Handbook of Research Synthesis and Meta-Analysis New York: Russell Sage Found, 2nd ed.. [Google Scholar]
• Cumming G 2014 . The new statistics: why and how. Psychol. Sci. 25 : 7– 29 Discusses the limitations of null hypothesis significance testing and viable alternative approaches. [Google Scholar]
• Earp BD , Trafimow D 2015 . Replication, falsification, and the crisis of confidence in social psychology. Front. Psychol. 6 : 621 [Google Scholar]
• Etz A , Vandekerckhove J 2016 . A Bayesian perspective on the reproducibility project: psychology. PLOS ONE 11 : e0149794 [Google Scholar]
• Ferguson CJ , Brannick MT 2012 . Publication bias in psychological science: prevalence, methods for identifying and controlling, and implications for the use of meta-analyses. Psychol. Methods 17 : 120– 28 [Google Scholar]
• Fleiss JL , Berlin JA 2009 . Effect sizes for dichotomous data. The Handbook of Research Synthesis and Meta-Analysis H Cooper, LV Hedges, JC Valentine 237– 53 New York: Russell Sage Found, 2nd ed.. [Google Scholar]
• Garside R 2014 . Should we appraise the quality of qualitative research reports for systematic reviews, and if so, how. Innovation 27 : 67– 79 [Google Scholar]
• Hedges LV , Olkin I 1980 . Vote count methods in research synthesis. Psychol. Bull. 88 : 359– 69 [Google Scholar]
• Hedges LV , Pigott TD 2001 . The power of statistical tests in meta-analysis. Psychol. Methods 6 : 203– 17 [Google Scholar]
• Higgins JPT , Green S 2011 . Cochrane Handbook for Systematic Reviews of Interventions, Version 5.1.0 London: Cochrane Collab. Presents comprehensive and regularly updated guidelines on systematic reviews. [Google Scholar]
• John LK , Loewenstein G , Prelec D 2012 . Measuring the prevalence of questionable research practices with incentives for truth telling. Psychol. Sci. 23 : 524– 32 [Google Scholar]
• Juni P , Witschi A , Bloch R , Egger M 1999 . The hazards of scoring the quality of clinical trials for meta-analysis. JAMA 282 : 1054– 60 [Google Scholar]
• Klein O , Doyen S , Leys C , Magalhães de Saldanha da Gama PA , Miller S et al. 2012 . Low hopes, high expectations: expectancy effects and the replicability of behavioral experiments. Perspect. Psychol. Sci. 7 : 6 572– 84 [Google Scholar]
• Lau J , Antman EM , Jimenez-Silva J , Kupelnick B , Mosteller F , Chalmers TC 1992 . Cumulative meta-analysis of therapeutic trials for myocardial infarction. N. Engl. J. Med. 327 : 248– 54 [Google Scholar]
• Light RJ , Smith PV 1971 . Accumulating evidence: procedures for resolving contradictions among different research studies. Harvard Educ. Rev. 41 : 429– 71 [Google Scholar]
• Lipsey MW , Wilson D 2001 . Practical Meta-Analysis London: Sage Comprehensive and clear explanation of meta-analysis. [Google Scholar]
• Matt GE , Cook TD 1994 . Threats to the validity of research synthesis. The Handbook of Research Synthesis H Cooper, LV Hedges 503– 20 New York: Russell Sage Found. [Google Scholar]
• Maxwell SE , Lau MY , Howard GS 2015 . Is psychology suffering from a replication crisis? What does “failure to replicate” really mean?. Am. Psychol. 70 : 487– 98 [Google Scholar]
• Moher D , Hopewell S , Schulz KF , Montori V , Gøtzsche PC et al. 2010 . CONSORT explanation and elaboration: updated guidelines for reporting parallel group randomised trials. BMJ 340 : c869 [Google Scholar]
• Moher D , Liberati A , Tetzlaff J , Altman DG PRISMA Group. 2009 . Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. BMJ 339 : 332– 36 Comprehensive reporting guidelines for systematic reviews. [Google Scholar]
• Morrison A , Polisena J , Husereau D , Moulton K , Clark M et al. 2012 . The effect of English-language restriction on systematic review-based meta-analyses: a systematic review of empirical studies. Int. J. Technol. Assess. Health Care 28 : 138– 44 [Google Scholar]
• Nelson LD , Simmons J , Simonsohn U 2018 . Psychology's renaissance. Annu. Rev. Psychol. 69 : 511– 34 [Google Scholar]
• Noblit GW , Hare RD 1988 . Meta-Ethnography: Synthesizing Qualitative Studies Newbury Park, CA: Sage [Google Scholar]
• Olivo SA , Macedo LG , Gadotti IC , Fuentes J , Stanton T , Magee DJ 2008 . Scales to assess the quality of randomized controlled trials: a systematic review. Phys. Ther. 88 : 156– 75 [Google Scholar]
• Open Sci. Collab. 2015 . Estimating the reproducibility of psychological science. Science 349 : 943 [Google Scholar]
• Paterson BL , Thorne SE , Canam C , Jillings C 2001 . Meta-Study of Qualitative Health Research: A Practical Guide to Meta-Analysis and Meta-Synthesis Thousand Oaks, CA: Sage [Google Scholar]
• Patil P , Peng RD , Leek JT 2016 . What should researchers expect when they replicate studies? A statistical view of replicability in psychological science. Perspect. Psychol. Sci. 11 : 539– 44 [Google Scholar]
• Rosenthal R 1979 . The “file drawer problem” and tolerance for null results. Psychol. Bull. 86 : 638– 41 [Google Scholar]
• Rosnow RL , Rosenthal R 1989 . Statistical procedures and the justification of knowledge in psychological science. Am. Psychol. 44 : 1276– 84 [Google Scholar]
• Sanderson S , Tatt ID , Higgins JP 2007 . Tools for assessing quality and susceptibility to bias in observational studies in epidemiology: a systematic review and annotated bibliography. Int. J. Epidemiol. 36 : 666– 76 [Google Scholar]
• Schreiber R , Crooks D , Stern PN 1997 . Qualitative meta-analysis. Completing a Qualitative Project: Details and Dialogue JM Morse 311– 26 Thousand Oaks, CA: Sage [Google Scholar]
• Shrout PE , Rodgers JL 2018 . Psychology, science, and knowledge construction: broadening perspectives from the replication crisis. Annu. Rev. Psychol. 69 : 487– 510 [Google Scholar]
• Stroebe W , Strack F 2014 . The alleged crisis and the illusion of exact replication. Perspect. Psychol. Sci. 9 : 59– 71 [Google Scholar]
• Stroup DF , Berlin JA , Morton SC , Olkin I , Williamson GD et al. 2000 . Meta-analysis of observational studies in epidemiology (MOOSE): a proposal for reporting. JAMA 283 : 2008– 12 [Google Scholar]
• Thorne S , Jensen L , Kearney MH , Noblit G , Sandelowski M 2004 . Qualitative meta-synthesis: reflections on methodological orientation and ideological agenda. Qual. Health Res. 14 : 1342– 65 [Google Scholar]
• Tong A , Flemming K , McInnes E , Oliver S , Craig J 2012 . Enhancing transparency in reporting the synthesis of qualitative research: ENTREQ. BMC Med. Res. Methodol. 12 : 181– 88 [Google Scholar]
• Trickey D , Siddaway AP , Meiser-Stedman R , Serpell L , Field AP 2012 . A meta-analysis of risk factors for post-traumatic stress disorder in children and adolescents. Clin. Psychol. Rev. 32 : 122– 38 [Google Scholar]
• Valentine JC , Biglan A , Boruch RF , Castro FG , Collins LM et al. 2011 . Replication in prevention science. Prev. Sci. 12 : 103– 17 [Google Scholar]
• Article Type: Review Article

Most Read This Month

Most cited most cited rss feed, job burnout, executive functions, social cognitive theory: an agentic perspective, on happiness and human potentials: a review of research on hedonic and eudaimonic well-being, sources of method bias in social science research and recommendations on how to control it, mediation analysis, missing data analysis: making it work in the real world, grounded cognition, personality structure: emergence of the five-factor model, motivational beliefs, values, and goals.

• Langson Library
• Science Library
• Grunigen Medical Library
• Law Library
• Connect From Off-Campus
• Accessibility
• Gateway Study Center

Email this link

Systematic reviews & evidence synthesis methods.

• Schedule a Consultation / Meet our Team
• What is Evidence Synthesis?
• Types of Evidence Synthesis
• Evidence Synthesis Across Disciplines
• Finding and Appraising Existing Systematic Reviews
• 0. Preliminary Searching
• 1. Develop a Protocol
• 2. Draft your Research Question
• 3. Select Databases
• 4. Select Grey Literature Sources
• 5. Write a Search Strategy
• 6. Register a Protocol
• 7. Translate Search Strategies
• 8. Citation Management
• 9. Article Screening
• 10. Risk of Bias Assessment
• 11. Data Extraction
• 12. Synthesize, Map, or Describe the Results
• Evidence Synthesis Resources & Tools

Requirements for the Systematic Review Process

Systematic reviews are a huge endeavor, so here are a few requirements if you are thinking of employing this methodology:

• Systematic reviews require time . 12-24 months is usual from conception to submission.
• Systematic reviews require a team . Four (4) or more team members are recommended. A principal investigator, a second investigator, a librarian, and someone well-versed in statistics forms the basic team. Ideally the team might have another investigator and someone to coordinate all the moving pieces. Smaller teams are possible, three is the realistic minimum . Two investigators each wearing more than one hat and one librarian. Sometimes an investigator has the time and energy to coordinate. Occasionally one of the investigators is also a statistical guru.
• * An exception to this rule is an "empty review," which retrieves zero studies that meet the inclusion criteria. Empty reviews are relatively uncommon, but may be used to demonstrate a need for future research in an area. However, an empty review may instead indicate that the research question was defined too narrowly. 

Why do a systematic review? A well done systematic review is a major contribution to the literature. But the requirements in time and effort are massive. Cochrane estimates one year from conception to completion. This does not including time for review, revision and publication. You need to assemble a team and they need to commit for the duration.

A good place to start is with a consultation with a librarian. Visit the " Schedule a Consultation " page to learn why.

• << Previous: Finding and Appraising Existing Systematic Reviews
• Next: 0. Preliminary Searching >>
• Last Updated: Aug 19, 2024 3:13 PM
• URL: https://guides.lib.uci.edu/evidence-synthesis

Off-campus? Please use the Software VPN and choose the group UCIFull to access licensed content. For more information, please Click here

Software VPN is not available for guests, so they may not have access to some content when connecting from off-campus.

Official websites use .gov

A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS

A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Systematic Reviews

Describes what is involved with conducting a systematic review of the literature for evidence-based public health and how the librarian is a partner in the process.

Several CDC librarians have special training in conducting literature searches for systematic reviews.  Literature searches for systematic reviews can take a few weeks to several months from planning to delivery.

Fill out a search request form here  or contact the Stephen B. Thacker CDC Library by email  [email protected] or telephone 404-639-1717.

Campbell Collaboration

Cochrane Collaboration

Eppi Centre

Joanna Briggs Institute

McMaster University

PRISMA Statement

Systematic Reviews – CRD’s Guide

Systematic Reviews of Health Promotion and Public Health Interventions

The Guide to Community Preventive Services

Look for systematic reviews that have already been published. 

• To ensure that the work has not already been done.
• To provides examples of search strategies for your topic

Look in PROSPERO for registered systematic reviews.

Search Cochrane and CRD-York for systematic reviews.

Search filter for finding systematic reviews in PubMed

Other search filters to locate systematic reviews

A systematic review attempts to collect and analyze all evidence that answers a specific question.  The question must be clearly defined and have inclusion and exclusion criteria. A broad and thorough search of the literature is performed and a critical analysis of the search results is reported and ultimately provides a current evidence-based answer  to the specific question.

Time:  According to Cochrane , it takes 18 months on average to complete a Systematic Review.

The average systematic review from beginning to end requires 18 months of work. “…to find out about a healthcare intervention it is worth searching research literature thoroughly to see if the answer is already known. This may require considerable work over many months…” ( Cochrane Collaboration )

Review Team: Team Members at minimum…

• Content expert
• 2 reviewers
• 1 tie breaker
• 1 statistician (meta-analysis)
• 1 economist if conducting an economic analysis
• *1 librarian (expert searcher) trained in systematic reviews

“Expert searchers are an important part of the systematic review team, crucial throughout the review process-from the development of the proposal and research question to publication.” ( McGowan & Sampson, 2005 )

*Ask your librarian to write a methods section regarding the search methods and to give them co-authorship. You may also want to consider providing a copy of one or all of the search strategies used in an appendix.

The Question to Be Answered: A clearly defined and specific question or questions with inclusion and exclusion criteria.

Written Protocol: Outline the study method, rationale, key questions, inclusion and exclusion criteria, literature searches, data abstraction and data management, analysis of quality of the individual studies, synthesis of data, and grading of the evidience for each key question.

Literature Searches:  Search for any systematic reviews that may already answer the key question(s).  Next, choose appropriate databases and conduct very broad, comprehensive searches.  Search strategies must be documented so that they can be duplicated.  The librarian is integral to this step of the process. Before your librarian creates a search strategy and starts searching in earnest you should write a detailed PICO question , determine the inclusion and exclusion criteria for your study, run a preliminary search, and have 2-4 articles that already fit the criteria for your review.

What is searched depends on the topic of the review but should include…

• At least 3 standard medical databases like PubMed/Medline, CINAHL, Embase, etc..
• At least 2 grey literature resources like Clinicaltrials.gov, COS Conference Papers Index, Grey Literature Report,  etc…

Citation Management: EndNote is a bibliographic management tools that assist researchers in managing citations.  The Stephen B. Thacker CDC Library oversees the site license for EndNote.

To request installation:   The library provides EndNote  to CDC staff under a site-wide license. Please use the ITSO Software Request Tool (SRT) and submit a request for the latest version (or upgraded version) of EndNote. Please be sure to include the computer name for the workstation where you would like to have the software installed.

EndNote Training:   CDC Library offers training on EndNote on a regular basis – both a basic and advanced course. To view the course descriptions and upcoming training dates, please visit the CDC Library training page .

For assistance with EndNote software, please contact [email protected]

Vendor Support and Services:   EndNote – Support and Services (Thomson Reuters)  EndNote – Tutorials and Live Online Classes (Thomson Reuters)

Getting Articles:

Articles can be obtained using DocExpress or by searching the electronic journals at the Stephen B. Thacker CDC Library.

IOM Standards for Systematic Reviews: Standard 3.1: Conduct a comprehensive systematic search for evidence

The goal of a systematic review search is to maximize recall and precision while keeping results manageable. Recall (sensitivity) is defined as the number of relevant reports identified divided by the total number of relevant reports in existence. Precision (specificity) is defined as the number of relevant reports identified divided by the total number of reports identified.

Issues to consider when creating a systematic review search:   

• All concepts are included in the strategy
• All appropriate subject headings are used
• Appropriate use of explosion
• Appropriate use of subheadings and floating subheadings
• Use of natural language (text words) in addition to controlled vocabulary terms
• Use of appropriate synonyms, acronyms, etc.
• Truncation and spelling variation as appropriate
• Appropriate use of limits such as language, years, etc.
• Field searching, publication type, author, etc.
• Boolean operators used appropriately
• Line errors: when searches are combined using line numbers, be sure the numbers refer to the searches intended
• Check indexing of relevant articles
• Search strategy adapted as needed for multiple databases
• Cochrane Handbook: Searching for Studies See Part 2, Chapter 6

A step-by-step guide to systematically identify all relevant animal studies

Materials listed in these guides are selected to provide awareness of quality public health literature and resources. A material’s inclusion does not necessarily represent the views of the U.S. Department of Health and Human Services (HHS), the Public Health Service (PHS), or the Centers for Disease Control and Prevention (CDC), nor does it imply endorsement of the material’s methods or findings. HHS, PHS, and CDC assume no responsibility for the factual accuracy of the items presented. The selection, omission, or content of items does not imply any endorsement or other position taken by HHS, PHS, and CDC. Opinion, findings, and conclusions expressed by the original authors of items included in these materials, or persons quoted therein, are strictly their own and are in no way meant to represent the opinion or views of HHS, PHS, or CDC. References to publications, news sources, and non-CDC Websites are provided solely for informational purposes and do not imply endorsement by HHS, PHS, or CDC.

• UNC Libraries
• HSL Academic Process
• Systematic Reviews

Systematic Reviews: Home

Created by health science librarians.

• Systematic review resources

What is a Systematic Review?

A simplified process map, how can the library help, publications by hsl librarians, systematic reviews in non-health disciplines, resources for performing systematic reviews.

• Step 1: Complete Pre-Review Tasks
• Step 2: Develop a Protocol
• Step 3: Conduct Literature Searches
• Step 4: Manage Citations
• Step 5: Screen Citations
• Step 6: Assess Quality of Included Studies
• Step 7: Extract Data from Included Studies
• Step 8: Write the Review

  Check our FAQ's

   Email us

   Call (919) 962-0800

   Make an appointment with a librarian

  Request a systematic or scoping review consultation

A systematic review is a literature review that gathers all of the available evidence matching pre-specified eligibility criteria to answer a specific research question. It uses explicit, systematic methods, documented in a protocol, to minimize bias , provide reliable findings , and inform decision-making.  ¹  

There are many types of literature reviews.

Before beginning a systematic review, consider whether it is the best type of review for your question, goals, and resources. The table below compares a few different types of reviews to help you decide which is best for you. 

• Scoping Review Guide For more information about scoping reviews, refer to the UNC HSL Scoping Review Guide.

• UNC HSL's Simplified, Step-by-Step Process Map A PDF file of the HSL's Systematic Review Process Map.
• Text-Only: UNC HSL's Systematic Reviews - A Simplified, Step-by-Step Process A text-only PDF file of HSL's Systematic Review Process Map.

The average systematic review takes 1,168 hours to complete. ¹   A librarian can help you speed up the process.

Systematic reviews follow established guidelines and best practices to produce high-quality research. Librarian involvement in systematic reviews is based on two levels. In Tier 1, your research team can consult with the librarian as needed. The librarian will answer questions and give you recommendations for tools to use. In Tier 2, the librarian will be an active member of your research team and co-author on your review. Roles and expectations of librarians vary based on the level of involvement desired. Examples of these differences are outlined in the table below.

• Request a systematic or scoping review consultation

The following are systematic and scoping reviews co-authored by HSL librarians.

Only the most recent 15 results are listed. Click the website link at the bottom of the list to see all reviews co-authored by HSL librarians in PubMed

Researchers conduct systematic reviews in a variety of disciplines.  If your focus is on a topic outside of the health sciences, you may want to also consult the resources below to learn how systematic reviews may vary in your field.  You can also contact a librarian for your discipline with questions.

• EPPI-Centre methods for conducting systematic reviews The EPPI-Centre develops methods and tools for conducting systematic reviews, including reviews for education, public and social policy.

Environmental Topics

• Collaboration for Environmental Evidence (CEE) CEE seeks to promote and deliver evidence syntheses on issues of greatest concern to environmental policy and practice as a public service

Social Sciences

• Siddaway AP, Wood AM, Hedges LV. How to Do a Systematic Review: A Best Practice Guide for Conducting and Reporting Narrative Reviews, Meta-Analyses, and Meta-Syntheses. Annu Rev Psychol. 2019 Jan 4;70:747-770. doi: 10.1146/annurev-psych-010418-102803. A resource for psychology systematic reviews, which also covers qualitative meta-syntheses or meta-ethnographies
• The Campbell Collaboration

Social Work

Software engineering

• Guidelines for Performing Systematic Literature Reviews in Software Engineering The objective of this report is to propose comprehensive guidelines for systematic literature reviews appropriate for software engineering researchers, including PhD students.

Sport, Exercise, & Nutrition

• Application of systematic review methodology to the field of nutrition by Tufts Evidence-based Practice Center Publication Date: 2009
• Systematic Reviews and Meta-Analysis — Open & Free (Open Learning Initiative) The course follows guidelines and standards developed by the Campbell Collaboration, based on empirical evidence about how to produce the most comprehensive and accurate reviews of research

• Systematic Reviews by David Gough, Sandy Oliver & James Thomas Publication Date: 2020

Updating reviews

• Updating systematic reviews by University of Ottawa Evidence-based Practice Center Publication Date: 2007
• Next: Step 1: Complete Pre-Review Tasks >>
• Last Updated: Jul 15, 2024 4:55 PM
• URL: https://guides.lib.unc.edu/systematic-reviews

• Open access
• Published: 14 August 2018

Defining the process to literature searching in systematic reviews: a literature review of guidance and supporting studies

• Chris Cooper   ORCID: orcid.org/0000-0003-0864-5607 1 ,
• Andrew Booth 2 ,
• Jo Varley-Campbell 1 ,
• Nicky Britten 3 &
• Ruth Garside 4  

BMC Medical Research Methodology volume  18 , Article number:  85 ( 2018 ) Cite this article

210k Accesses

224 Citations

117 Altmetric

Metrics details

Systematic literature searching is recognised as a critical component of the systematic review process. It involves a systematic search for studies and aims for a transparent report of study identification, leaving readers clear about what was done to identify studies, and how the findings of the review are situated in the relevant evidence.

Information specialists and review teams appear to work from a shared and tacit model of the literature search process. How this tacit model has developed and evolved is unclear, and it has not been explicitly examined before.

The purpose of this review is to determine if a shared model of the literature searching process can be detected across systematic review guidance documents and, if so, how this process is reported in the guidance and supported by published studies.

A literature review.

Two types of literature were reviewed: guidance and published studies. Nine guidance documents were identified, including: The Cochrane and Campbell Handbooks. Published studies were identified through ‘pearl growing’, citation chasing, a search of PubMed using the systematic review methods filter, and the authors’ topic knowledge.

The relevant sections within each guidance document were then read and re-read, with the aim of determining key methodological stages. Methodological stages were identified and defined. This data was reviewed to identify agreements and areas of unique guidance between guidance documents. Consensus across multiple guidance documents was used to inform selection of ‘key stages’ in the process of literature searching.

Eight key stages were determined relating specifically to literature searching in systematic reviews. They were: who should literature search, aims and purpose of literature searching, preparation, the search strategy, searching databases, supplementary searching, managing references and reporting the search process.

Conclusions

Eight key stages to the process of literature searching in systematic reviews were identified. These key stages are consistently reported in the nine guidance documents, suggesting consensus on the key stages of literature searching, and therefore the process of literature searching as a whole, in systematic reviews. Further research to determine the suitability of using the same process of literature searching for all types of systematic review is indicated.

Peer Review reports

Systematic literature searching is recognised as a critical component of the systematic review process. It involves a systematic search for studies and aims for a transparent report of study identification, leaving review stakeholders clear about what was done to identify studies, and how the findings of the review are situated in the relevant evidence.

Information specialists and review teams appear to work from a shared and tacit model of the literature search process. How this tacit model has developed and evolved is unclear, and it has not been explicitly examined before. This is in contrast to the information science literature, which has developed information processing models as an explicit basis for dialogue and empirical testing. Without an explicit model, research in the process of systematic literature searching will remain immature and potentially uneven, and the development of shared information models will be assumed but never articulated.

One way of developing such a conceptual model is by formally examining the implicit “programme theory” as embodied in key methodological texts. The aim of this review is therefore to determine if a shared model of the literature searching process in systematic reviews can be detected across guidance documents and, if so, how this process is reported and supported.

Identifying guidance

Key texts (henceforth referred to as “guidance”) were identified based upon their accessibility to, and prominence within, United Kingdom systematic reviewing practice. The United Kingdom occupies a prominent position in the science of health information retrieval, as quantified by such objective measures as the authorship of papers, the number of Cochrane groups based in the UK, membership and leadership of groups such as the Cochrane Information Retrieval Methods Group, the HTA-I Information Specialists’ Group and historic association with such centres as the UK Cochrane Centre, the NHS Centre for Reviews and Dissemination, the Centre for Evidence Based Medicine and the National Institute for Clinical Excellence (NICE). Coupled with the linguistic dominance of English within medical and health science and the science of systematic reviews more generally, this offers a justification for a purposive sample that favours UK, European and Australian guidance documents.

Nine guidance documents were identified. These documents provide guidance for different types of reviews, namely: reviews of interventions, reviews of health technologies, reviews of qualitative research studies, reviews of social science topics, and reviews to inform guidance.

Whilst these guidance documents occasionally offer additional guidance on other types of systematic reviews, we have focused on the core and stated aims of these documents as they relate to literature searching. Table  1 sets out: the guidance document, the version audited, their core stated focus, and a bibliographical pointer to the main guidance relating to literature searching.

Once a list of key guidance documents was determined, it was checked by six senior information professionals based in the UK for relevance to current literature searching in systematic reviews.

Identifying supporting studies

In addition to identifying guidance, the authors sought to populate an evidence base of supporting studies (henceforth referred to as “studies”) that contribute to existing search practice. Studies were first identified by the authors from their knowledge on this topic area and, subsequently, through systematic citation chasing key studies (‘pearls’ [ 1 ]) located within each key stage of the search process. These studies are identified in Additional file  1 : Appendix Table 1. Citation chasing was conducted by analysing the bibliography of references for each study (backwards citation chasing) and through Google Scholar (forward citation chasing). A search of PubMed using the systematic review methods filter was undertaken in August 2017 (see Additional file 1 ). The search terms used were: (literature search*[Title/Abstract]) AND sysrev_methods[sb] and 586 results were returned. These results were sifted for relevance to the key stages in Fig.  1 by CC.

The key stages of literature search guidance as identified from nine key texts

Extracting the data

To reveal the implicit process of literature searching within each guidance document, the relevant sections (chapters) on literature searching were read and re-read, with the aim of determining key methodological stages. We defined a key methodological stage as a distinct step in the overall process for which specific guidance is reported, and action is taken, that collectively would result in a completed literature search.

The chapter or section sub-heading for each methodological stage was extracted into a table using the exact language as reported in each guidance document. The lead author (CC) then read and re-read these data, and the paragraphs of the document to which the headings referred, summarising section details. This table was then reviewed, using comparison and contrast to identify agreements and areas of unique guidance. Consensus across multiple guidelines was used to inform selection of ‘key stages’ in the process of literature searching.

Having determined the key stages to literature searching, we then read and re-read the sections relating to literature searching again, extracting specific detail relating to the methodological process of literature searching within each key stage. Again, the guidance was then read and re-read, first on a document-by-document-basis and, secondly, across all the documents above, to identify both commonalities and areas of unique guidance.

Results and discussion

Our findings.

We were able to identify consensus across the guidance on literature searching for systematic reviews suggesting a shared implicit model within the information retrieval community. Whilst the structure of the guidance varies between documents, the same key stages are reported, even where the core focus of each document is different. We were able to identify specific areas of unique guidance, where a document reported guidance not summarised in other documents, together with areas of consensus across guidance.

Unique guidance

Only one document provided guidance on the topic of when to stop searching [ 2 ]. This guidance from 2005 anticipates a topic of increasing importance with the current interest in time-limited (i.e. “rapid”) reviews. Quality assurance (or peer review) of literature searches was only covered in two guidance documents [ 3 , 4 ]. This topic has emerged as increasingly important as indicated by the development of the PRESS instrument [ 5 ]. Text mining was discussed in four guidance documents [ 4 , 6 , 7 , 8 ] where the automation of some manual review work may offer efficiencies in literature searching [ 8 ].

Agreement between guidance: Defining the key stages of literature searching

Where there was agreement on the process, we determined that this constituted a key stage in the process of literature searching to inform systematic reviews.

From the guidance, we determined eight key stages that relate specifically to literature searching in systematic reviews. These are summarised at Fig. 1 . The data extraction table to inform Fig. 1 is reported in Table  2 . Table 2 reports the areas of common agreement and it demonstrates that the language used to describe key stages and processes varies significantly between guidance documents.

For each key stage, we set out the specific guidance, followed by discussion on how this guidance is situated within the wider literature.

Key stage one: Deciding who should undertake the literature search

The guidance.

Eight documents provided guidance on who should undertake literature searching in systematic reviews [ 2 , 4 , 6 , 7 , 8 , 9 , 10 , 11 ]. The guidance affirms that people with relevant expertise of literature searching should ‘ideally’ be included within the review team [ 6 ]. Information specialists (or information scientists), librarians or trial search co-ordinators (TSCs) are indicated as appropriate researchers in six guidance documents [ 2 , 7 , 8 , 9 , 10 , 11 ].

How the guidance corresponds to the published studies

The guidance is consistent with studies that call for the involvement of information specialists and librarians in systematic reviews [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ] and which demonstrate how their training as ‘expert searchers’ and ‘analysers and organisers of data’ can be put to good use [ 13 ] in a variety of roles [ 12 , 16 , 20 , 21 , 24 , 25 , 26 ]. These arguments make sense in the context of the aims and purposes of literature searching in systematic reviews, explored below. The need for ‘thorough’ and ‘replicable’ literature searches was fundamental to the guidance and recurs in key stage two. Studies have found poor reporting, and a lack of replicable literature searches, to be a weakness in systematic reviews [ 17 , 18 , 27 , 28 ] and they argue that involvement of information specialists/ librarians would be associated with better reporting and better quality literature searching. Indeed, Meert et al. [ 29 ] demonstrated that involving a librarian as a co-author to a systematic review correlated with a higher score in the literature searching component of a systematic review [ 29 ]. As ‘new styles’ of rapid and scoping reviews emerge, where decisions on how to search are more iterative and creative, a clear role is made here too [ 30 ].

Knowing where to search for studies was noted as important in the guidance, with no agreement as to the appropriate number of databases to be searched [ 2 , 6 ]. Database (and resource selection more broadly) is acknowledged as a relevant key skill of information specialists and librarians [ 12 , 15 , 16 , 31 ].

Whilst arguments for including information specialists and librarians in the process of systematic review might be considered self-evident, Koffel and Rethlefsen [ 31 ] have questioned if the necessary involvement is actually happening [ 31 ].

Key stage two: Determining the aim and purpose of a literature search

The aim: Five of the nine guidance documents use adjectives such as ‘thorough’, ‘comprehensive’, ‘transparent’ and ‘reproducible’ to define the aim of literature searching [ 6 , 7 , 8 , 9 , 10 ]. Analogous phrases were present in a further three guidance documents, namely: ‘to identify the best available evidence’ [ 4 ] or ‘the aim of the literature search is not to retrieve everything. It is to retrieve everything of relevance’ [ 2 ] or ‘A systematic literature search aims to identify all publications relevant to the particular research question’ [ 3 ]. The Joanna Briggs Institute reviewers’ manual was the only guidance document where a clear statement on the aim of literature searching could not be identified. The purpose of literature searching was defined in three guidance documents, namely to minimise bias in the resultant review [ 6 , 8 , 10 ]. Accordingly, eight of nine documents clearly asserted that thorough and comprehensive literature searches are required as a potential mechanism for minimising bias.

The need for thorough and comprehensive literature searches appears as uniform within the eight guidance documents that describe approaches to literature searching in systematic reviews of effectiveness. Reviews of effectiveness (of intervention or cost), accuracy and prognosis, require thorough and comprehensive literature searches to transparently produce a reliable estimate of intervention effect. The belief that all relevant studies have been ‘comprehensively’ identified, and that this process has been ‘transparently’ reported, increases confidence in the estimate of effect and the conclusions that can be drawn [ 32 ]. The supporting literature exploring the need for comprehensive literature searches focuses almost exclusively on reviews of intervention effectiveness and meta-analysis. Different ‘styles’ of review may have different standards however; the alternative, offered by purposive sampling, has been suggested in the specific context of qualitative evidence syntheses [ 33 ].

What is a comprehensive literature search?

Whilst the guidance calls for thorough and comprehensive literature searches, it lacks clarity on what constitutes a thorough and comprehensive literature search, beyond the implication that all of the literature search methods in Table 2 should be used to identify studies. Egger et al. [ 34 ], in an empirical study evaluating the importance of comprehensive literature searches for trials in systematic reviews, defined a comprehensive search for trials as:

a search not restricted to English language;

where Cochrane CENTRAL or at least two other electronic databases had been searched (such as MEDLINE or EMBASE); and

at least one of the following search methods has been used to identify unpublished trials: searches for (I) conference abstracts, (ii) theses, (iii) trials registers; and (iv) contacts with experts in the field [ 34 ].

Tricco et al. (2008) used a similar threshold of bibliographic database searching AND a supplementary search method in a review when examining the risk of bias in systematic reviews. Their criteria were: one database (limited using the Cochrane Highly Sensitive Search Strategy (HSSS)) and handsearching [ 35 ].

Together with the guidance, this would suggest that comprehensive literature searching requires the use of BOTH bibliographic database searching AND supplementary search methods.

Comprehensiveness in literature searching, in the sense of how much searching should be undertaken, remains unclear. Egger et al. recommend that ‘investigators should consider the type of literature search and degree of comprehension that is appropriate for the review in question, taking into account budget and time constraints’ [ 34 ]. This view tallies with the Cochrane Handbook, which stipulates clearly, that study identification should be undertaken ‘within resource limits’ [ 9 ]. This would suggest that the limitations to comprehension are recognised but it raises questions on how this is decided and reported [ 36 ].

What is the point of comprehensive literature searching?

The purpose of thorough and comprehensive literature searches is to avoid missing key studies and to minimize bias [ 6 , 8 , 10 , 34 , 37 , 38 , 39 ] since a systematic review based only on published (or easily accessible) studies may have an exaggerated effect size [ 35 ]. Felson (1992) sets out potential biases that could affect the estimate of effect in a meta-analysis [ 40 ] and Tricco et al. summarize the evidence concerning bias and confounding in systematic reviews [ 35 ]. Egger et al. point to non-publication of studies, publication bias, language bias and MEDLINE bias, as key biases [ 34 , 35 , 40 , 41 , 42 , 43 , 44 , 45 , 46 ]. Comprehensive searches are not the sole factor to mitigate these biases but their contribution is thought to be significant [ 2 , 32 , 34 ]. Fehrmann (2011) suggests that ‘the search process being described in detail’ and that, where standard comprehensive search techniques have been applied, increases confidence in the search results [ 32 ].

Does comprehensive literature searching work?

Egger et al., and other study authors, have demonstrated a change in the estimate of intervention effectiveness where relevant studies were excluded from meta-analysis [ 34 , 47 ]. This would suggest that missing studies in literature searching alters the reliability of effectiveness estimates. This is an argument for comprehensive literature searching. Conversely, Egger et al. found that ‘comprehensive’ searches still missed studies and that comprehensive searches could, in fact, introduce bias into a review rather than preventing it, through the identification of low quality studies then being included in the meta-analysis [ 34 ]. Studies query if identifying and including low quality or grey literature studies changes the estimate of effect [ 43 , 48 ] and question if time is better invested updating systematic reviews rather than searching for unpublished studies [ 49 ], or mapping studies for review as opposed to aiming for high sensitivity in literature searching [ 50 ].

Aim and purpose beyond reviews of effectiveness

The need for comprehensive literature searches is less certain in reviews of qualitative studies, and for reviews where a comprehensive identification of studies is difficult to achieve (for example, in Public health) [ 33 , 51 , 52 , 53 , 54 , 55 ]. Literature searching for qualitative studies, and in public health topics, typically generates a greater number of studies to sift than in reviews of effectiveness [ 39 ] and demonstrating the ‘value’ of studies identified or missed is harder [ 56 ], since the study data do not typically support meta-analysis. Nussbaumer-Streit et al. (2016) have registered a review protocol to assess whether abbreviated literature searches (as opposed to comprehensive literature searches) has an impact on conclusions across multiple bodies of evidence, not only on effect estimates [ 57 ] which may develop this understanding. It may be that decision makers and users of systematic reviews are willing to trade the certainty from a comprehensive literature search and systematic review in exchange for different approaches to evidence synthesis [ 58 ], and that comprehensive literature searches are not necessarily a marker of literature search quality, as previously thought [ 36 ]. Different approaches to literature searching [ 37 , 38 , 59 , 60 , 61 , 62 ] and developing the concept of when to stop searching are important areas for further study [ 36 , 59 ].

The study by Nussbaumer-Streit et al. has been published since the submission of this literature review [ 63 ]. Nussbaumer-Streit et al. (2018) conclude that abbreviated literature searches are viable options for rapid evidence syntheses, if decision-makers are willing to trade the certainty from a comprehensive literature search and systematic review, but that decision-making which demands detailed scrutiny should still be based on comprehensive literature searches [ 63 ].

Key stage three: Preparing for the literature search

Six documents provided guidance on preparing for a literature search [ 2 , 3 , 6 , 7 , 9 , 10 ]. The Cochrane Handbook clearly stated that Cochrane authors (i.e. researchers) should seek advice from a trial search co-ordinator (i.e. a person with specific skills in literature searching) ‘before’ starting a literature search [ 9 ].

Two key tasks were perceptible in preparing for a literature searching [ 2 , 6 , 7 , 10 , 11 ]. First, to determine if there are any existing or on-going reviews, or if a new review is justified [ 6 , 11 ]; and, secondly, to develop an initial literature search strategy to estimate the volume of relevant literature (and quality of a small sample of relevant studies [ 10 ]) and indicate the resources required for literature searching and the review of the studies that follows [ 7 , 10 ].

Three documents summarised guidance on where to search to determine if a new review was justified [ 2 , 6 , 11 ]. These focused on searching databases of systematic reviews (The Cochrane Database of Systematic Reviews (CDSR) and the Database of Abstracts of Reviews of Effects (DARE)), institutional registries (including PROSPERO), and MEDLINE [ 6 , 11 ]. It is worth noting, however, that as of 2015, DARE (and NHS EEDs) are no longer being updated and so the relevance of this (these) resource(s) will diminish over-time [ 64 ]. One guidance document, ‘Systematic reviews in the Social Sciences’, noted, however, that databases are not the only source of information and unpublished reports, conference proceeding and grey literature may also be required, depending on the nature of the review question [ 2 ].

Two documents reported clearly that this preparation (or ‘scoping’) exercise should be undertaken before the actual search strategy is developed [ 7 , 10 ]).

The guidance offers the best available source on preparing the literature search with the published studies not typically reporting how their scoping informed the development of their search strategies nor how their search approaches were developed. Text mining has been proposed as a technique to develop search strategies in the scoping stages of a review although this work is still exploratory [ 65 ]. ‘Clustering documents’ and word frequency analysis have also been tested to identify search terms and studies for review [ 66 , 67 ]. Preparing for literature searches and scoping constitutes an area for future research.

Key stage four: Designing the search strategy

The Population, Intervention, Comparator, Outcome (PICO) structure was the commonly reported structure promoted to design a literature search strategy. Five documents suggested that the eligibility criteria or review question will determine which concepts of PICO will be populated to develop the search strategy [ 1 , 4 , 7 , 8 , 9 ]. The NICE handbook promoted multiple structures, namely PICO, SPICE (Setting, Perspective, Intervention, Comparison, Evaluation) and multi-stranded approaches [ 4 ].

With the exclusion of The Joanna Briggs Institute reviewers’ manual, the guidance offered detail on selecting key search terms, synonyms, Boolean language, selecting database indexing terms and combining search terms. The CEE handbook suggested that ‘search terms may be compiled with the help of the commissioning organisation and stakeholders’ [ 10 ].

The use of limits, such as language or date limits, were discussed in all documents [ 2 , 3 , 4 , 6 , 7 , 8 , 9 , 10 , 11 ].

Search strategy structure

The guidance typically relates to reviews of intervention effectiveness so PICO – with its focus on intervention and comparator - is the dominant model used to structure literature search strategies [ 68 ]. PICOs – where the S denotes study design - is also commonly used in effectiveness reviews [ 6 , 68 ]. As the NICE handbook notes, alternative models to structure literature search strategies have been developed and tested. Booth provides an overview on formulating questions for evidence based practice [ 69 ] and has developed a number of alternatives to the PICO structure, namely: BeHEMoTh (Behaviour of interest; Health context; Exclusions; Models or Theories) for use when systematically identifying theory [ 55 ]; SPICE (Setting, Perspective, Intervention, Comparison, Evaluation) for identification of social science and evaluation studies [ 69 ] and, working with Cooke and colleagues, SPIDER (Sample, Phenomenon of Interest, Design, Evaluation, Research type) [ 70 ]. SPIDER has been compared to PICO and PICOs in a study by Methley et al. [ 68 ].

The NICE handbook also suggests the use of multi-stranded approaches to developing literature search strategies [ 4 ]. Glanville developed this idea in a study by Whitting et al. [ 71 ] and a worked example of this approach is included in the development of a search filter by Cooper et al. [ 72 ].

Writing search strategies: Conceptual and objective approaches

Hausner et al. [ 73 ] provide guidance on writing literature search strategies, delineating between conceptually and objectively derived approaches. The conceptual approach, advocated by and explained in the guidance documents, relies on the expertise of the literature searcher to identify key search terms and then develop key terms to include synonyms and controlled syntax. Hausner and colleagues set out the objective approach [ 73 ] and describe what may be done to validate it [ 74 ].

The use of limits

The guidance documents offer direction on the use of limits within a literature search. Limits can be used to focus literature searching to specific study designs or by other markers (such as by date) which limits the number of studies returned by a literature search. The use of limits should be described and the implications explored [ 34 ] since limiting literature searching can introduce bias (explored above). Craven et al. have suggested the use of a supporting narrative to explain decisions made in the process of developing literature searches and this advice would usefully capture decisions on the use of search limits [ 75 ].

Key stage five: Determining the process of literature searching and deciding where to search (bibliographic database searching)

Table 2 summarises the process of literature searching as reported in each guidance document. Searching bibliographic databases was consistently reported as the ‘first step’ to literature searching in all nine guidance documents.

Three documents reported specific guidance on where to search, in each case specific to the type of review their guidance informed, and as a minimum requirement [ 4 , 9 , 11 ]. Seven of the key guidance documents suggest that the selection of bibliographic databases depends on the topic of review [ 2 , 3 , 4 , 6 , 7 , 8 , 10 ], with two documents noting the absence of an agreed standard on what constitutes an acceptable number of databases searched [ 2 , 6 ].

The guidance documents summarise ‘how to’ search bibliographic databases in detail and this guidance is further contextualised above in terms of developing the search strategy. The documents provide guidance of selecting bibliographic databases, in some cases stating acceptable minima (i.e. The Cochrane Handbook states Cochrane CENTRAL, MEDLINE and EMBASE), and in other cases simply listing bibliographic database available to search. Studies have explored the value in searching specific bibliographic databases, with Wright et al. (2015) noting the contribution of CINAHL in identifying qualitative studies [ 76 ], Beckles et al. (2013) questioning the contribution of CINAHL to identifying clinical studies for guideline development [ 77 ], and Cooper et al. (2015) exploring the role of UK-focused bibliographic databases to identify UK-relevant studies [ 78 ]. The host of the database (e.g. OVID or ProQuest) has been shown to alter the search returns offered. Younger and Boddy [ 79 ] report differing search returns from the same database (AMED) but where the ‘host’ was different [ 79 ].

The average number of bibliographic database searched in systematic reviews has risen in the period 1994–2014 (from 1 to 4) [ 80 ] but there remains (as attested to by the guidance) no consensus on what constitutes an acceptable number of databases searched [ 48 ]. This is perhaps because thinking about the number of databases searched is the wrong question, researchers should be focused on which databases were searched and why, and which databases were not searched and why. The discussion should re-orientate to the differential value of sources but researchers need to think about how to report this in studies to allow findings to be generalised. Bethel (2017) has proposed ‘search summaries’, completed by the literature searcher, to record where included studies were identified, whether from database (and which databases specifically) or supplementary search methods [ 81 ]. Search summaries document both yield and accuracy of searches, which could prospectively inform resource use and decisions to search or not to search specific databases in topic areas. The prospective use of such data presupposes, however, that past searches are a potential predictor of future search performance (i.e. that each topic is to be considered representative and not unique). In offering a body of practice, this data would be of greater practicable use than current studies which are considered as little more than individual case studies [ 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 ].

When to database search is another question posed in the literature. Beyer et al. [ 91 ] report that databases can be prioritised for literature searching which, whilst not addressing the question of which databases to search, may at least bring clarity as to which databases to search first [ 91 ]. Paradoxically, this links to studies that suggest PubMed should be searched in addition to MEDLINE (OVID interface) since this improves the currency of systematic reviews [ 92 , 93 ]. Cooper et al. (2017) have tested the idea of database searching not as a primary search method (as suggested in the guidance) but as a supplementary search method in order to manage the volume of studies identified for an environmental effectiveness systematic review. Their case study compared the effectiveness of database searching versus a protocol using supplementary search methods and found that the latter identified more relevant studies for review than searching bibliographic databases [ 94 ].

Key stage six: Determining the process of literature searching and deciding where to search (supplementary search methods)

Table 2 also summaries the process of literature searching which follows bibliographic database searching. As Table 2 sets out, guidance that supplementary literature search methods should be used in systematic reviews recurs across documents, but the order in which these methods are used, and the extent to which they are used, varies. We noted inconsistency in the labelling of supplementary search methods between guidance documents.

Rather than focus on the guidance on how to use the methods (which has been summarised in a recent review [ 95 ]), we focus on the aim or purpose of supplementary search methods.

The Cochrane Handbook reported that ‘efforts’ to identify unpublished studies should be made [ 9 ]. Four guidance documents [ 2 , 3 , 6 , 9 ] acknowledged that searching beyond bibliographic databases was necessary since ‘databases are not the only source of literature’ [ 2 ]. Only one document reported any guidance on determining when to use supplementary methods. The IQWiG handbook reported that the use of handsearching (in their example) could be determined on a ‘case-by-case basis’ which implies that the use of these methods is optional rather than mandatory. This is in contrast to the guidance (above) on bibliographic database searching.

The issue for supplementary search methods is similar in many ways to the issue of searching bibliographic databases: demonstrating value. The purpose and contribution of supplementary search methods in systematic reviews is increasingly acknowledged [ 37 , 61 , 62 , 96 , 97 , 98 , 99 , 100 , 101 ] but understanding the value of the search methods to identify studies and data is unclear. In a recently published review, Cooper et al. (2017) reviewed the literature on supplementary search methods looking to determine the advantages, disadvantages and resource implications of using supplementary search methods [ 95 ]. This review also summarises the key guidance and empirical studies and seeks to address the question on when to use these search methods and when not to [ 95 ]. The guidance is limited in this regard and, as Table 2 demonstrates, offers conflicting advice on the order of searching, and the extent to which these search methods should be used in systematic reviews.

Key stage seven: Managing the references

Five of the documents provided guidance on managing references, for example downloading, de-duplicating and managing the output of literature searches [ 2 , 4 , 6 , 8 , 10 ]. This guidance typically itemised available bibliographic management tools rather than offering guidance on how to use them specifically [ 2 , 4 , 6 , 8 ]. The CEE handbook provided guidance on importing data where no direct export option is available (e.g. web-searching) [ 10 ].

The literature on using bibliographic management tools is not large relative to the number of ‘how to’ videos on platforms such as YouTube (see for example [ 102 ]). These YouTube videos confirm the overall lack of ‘how to’ guidance identified in this study and offer useful instruction on managing references. Bramer et al. set out methods for de-duplicating data and reviewing references in Endnote [ 103 , 104 ] and Gall tests the direct search function within Endnote to access databases such as PubMed, finding a number of limitations [ 105 ]. Coar et al. and Ahmed et al. consider the role of the free-source tool, Zotero [ 106 , 107 ]. Managing references is a key administrative function in the process of review particularly for documenting searches in PRISMA guidance.

Key stage eight: Documenting the search

The Cochrane Handbook was the only guidance document to recommend a specific reporting guideline: Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) [ 9 ]. Six documents provided guidance on reporting the process of literature searching with specific criteria to report [ 3 , 4 , 6 , 8 , 9 , 10 ]. There was consensus on reporting: the databases searched (and the host searched by), the search strategies used, and any use of limits (e.g. date, language, search filters (The CRD handbook called for these limits to be justified [ 6 ])). Three guidance documents reported that the number of studies identified should be recorded [ 3 , 6 , 10 ]. The number of duplicates identified [ 10 ], the screening decisions [ 3 ], a comprehensive list of grey literature sources searched (and full detail for other supplementary search methods) [ 8 ], and an annotation of search terms tested but not used [ 4 ] were identified as unique items in four documents.

The Cochrane Handbook was the only guidance document to note that the full search strategies for each database should be included in the Additional file 1 of the review [ 9 ].

All guidance documents should ultimately deliver completed systematic reviews that fulfil the requirements of the PRISMA reporting guidelines [ 108 ]. The guidance broadly requires the reporting of data that corresponds with the requirements of the PRISMA statement although documents typically ask for diverse and additional items [ 108 ]. In 2008, Sampson et al. observed a lack of consensus on reporting search methods in systematic reviews [ 109 ] and this remains the case as of 2017, as evidenced in the guidance documents, and in spite of the publication of the PRISMA guidelines in 2009 [ 110 ]. It is unclear why the collective guidance does not more explicitly endorse adherence to the PRISMA guidance.

Reporting of literature searching is a key area in systematic reviews since it sets out clearly what was done and how the conclusions of the review can be believed [ 52 , 109 ]. Despite strong endorsement in the guidance documents, specifically supported in PRISMA guidance, and other related reporting standards too (such as ENTREQ for qualitative evidence synthesis, STROBE for reviews of observational studies), authors still highlight the prevalence of poor standards of literature search reporting [ 31 , 110 , 111 , 112 , 113 , 114 , 115 , 116 , 117 , 118 , 119 ]. To explore issues experienced by authors in reporting literature searches, and look at uptake of PRISMA, Radar et al. [ 120 ] surveyed over 260 review authors to determine common problems and their work summaries the practical aspects of reporting literature searching [ 120 ]. Atkinson et al. [ 121 ] have also analysed reporting standards for literature searching, summarising recommendations and gaps for reporting search strategies [ 121 ].

One area that is less well covered by the guidance, but nevertheless appears in this literature, is the quality appraisal or peer review of literature search strategies. The PRESS checklist is the most prominent and it aims to develop evidence-based guidelines to peer review of electronic search strategies [ 5 , 122 , 123 ]. A corresponding guideline for documentation of supplementary search methods does not yet exist although this idea is currently being explored.

How the reporting of the literature searching process corresponds to critical appraisal tools is an area for further research. In the survey undertaken by Radar et al. (2014), 86% of survey respondents (153/178) identified a need for further guidance on what aspects of the literature search process to report [ 120 ]. The PRISMA statement offers a brief summary of what to report but little practical guidance on how to report it [ 108 ]. Critical appraisal tools for systematic reviews, such as AMSTAR 2 (Shea et al. [ 124 ]) and ROBIS (Whiting et al. [ 125 ]), can usefully be read alongside PRISMA guidance, since they offer greater detail on how the reporting of the literature search will be appraised and, therefore, they offer a proxy on what to report [ 124 , 125 ]. Further research in the form of a study which undertakes a comparison between PRISMA and quality appraisal checklists for systematic reviews would seem to begin addressing the call, identified by Radar et al., for further guidance on what to report [ 120 ].

Limitations

Other handbooks exist.

A potential limitation of this literature review is the focus on guidance produced in Europe (the UK specifically) and Australia. We justify the decision for our selection of the nine guidance documents reviewed in this literature review in section “ Identifying guidance ”. In brief, these nine guidance documents were selected as the most relevant health care guidance that inform UK systematic reviewing practice, given that the UK occupies a prominent position in the science of health information retrieval. We acknowledge the existence of other guidance documents, such as those from North America (e.g. the Agency for Healthcare Research and Quality (AHRQ) [ 126 ], The Institute of Medicine [ 127 ] and the guidance and resources produced by the Canadian Agency for Drugs and Technologies in Health (CADTH) [ 128 ]). We comment further on this directly below.

The handbooks are potentially linked to one another

What is not clear is the extent to which the guidance documents inter-relate or provide guidance uniquely. The Cochrane Handbook, first published in 1994, is notably a key source of reference in guidance and systematic reviews beyond Cochrane reviews. It is not clear to what extent broadening the sample of guidance handbooks to include North American handbooks, and guidance handbooks from other relevant countries too, would alter the findings of this literature review or develop further support for the process model. Since we cannot be clear, we raise this as a potential limitation of this literature review. On our initial review of a sample of North American, and other, guidance documents (before selecting the guidance documents considered in this review), however, we do not consider that the inclusion of these further handbooks would alter significantly the findings of this literature review.

This is a literature review

A further limitation of this review was that the review of published studies is not a systematic review of the evidence for each key stage. It is possible that other relevant studies could help contribute to the exploration and development of the key stages identified in this review.

This literature review would appear to demonstrate the existence of a shared model of the literature searching process in systematic reviews. We call this model ‘the conventional approach’, since it appears to be common convention in nine different guidance documents.

The findings reported above reveal eight key stages in the process of literature searching for systematic reviews. These key stages are consistently reported in the nine guidance documents which suggests consensus on the key stages of literature searching, and therefore the process of literature searching as a whole, in systematic reviews.

In Table 2 , we demonstrate consensus regarding the application of literature search methods. All guidance documents distinguish between primary and supplementary search methods. Bibliographic database searching is consistently the first method of literature searching referenced in each guidance document. Whilst the guidance uniformly supports the use of supplementary search methods, there is little evidence for a consistent process with diverse guidance across documents. This may reflect differences in the core focus across each document, linked to differences in identifying effectiveness studies or qualitative studies, for instance.

Eight of the nine guidance documents reported on the aims of literature searching. The shared understanding was that literature searching should be thorough and comprehensive in its aim and that this process should be reported transparently so that that it could be reproduced. Whilst only three documents explicitly link this understanding to minimising bias, it is clear that comprehensive literature searching is implicitly linked to ‘not missing relevant studies’ which is approximately the same point.

Defining the key stages in this review helps categorise the scholarship available, and it prioritises areas for development or further study. The supporting studies on preparing for literature searching (key stage three, ‘preparation’) were, for example, comparatively few, and yet this key stage represents a decisive moment in literature searching for systematic reviews. It is where search strategy structure is determined, search terms are chosen or discarded, and the resources to be searched are selected. Information specialists, librarians and researchers, are well placed to develop these and other areas within the key stages we identify.

This review calls for further research to determine the suitability of using the conventional approach. The publication dates of the guidance documents which underpin the conventional approach may raise questions as to whether the process which they each report remains valid for current systematic literature searching. In addition, it may be useful to test whether it is desirable to use the same process model of literature searching for qualitative evidence synthesis as that for reviews of intervention effectiveness, which this literature review demonstrates is presently recommended best practice.

Abbreviations

Behaviour of interest; Health context; Exclusions; Models or Theories

Cochrane Database of Systematic Reviews

The Cochrane Central Register of Controlled Trials

Database of Abstracts of Reviews of Effects

Enhancing transparency in reporting the synthesis of qualitative research

Institute for Quality and Efficiency in Healthcare

National Institute for Clinical Excellence

Population, Intervention, Comparator, Outcome

Preferred Reporting Items for Systematic Reviews and Meta-Analyses

Setting, Perspective, Intervention, Comparison, Evaluation

Sample, Phenomenon of Interest, Design, Evaluation, Research type

STrengthening the Reporting of OBservational studies in Epidemiology

Trial Search Co-ordinators

Booth A. Unpacking your literature search toolbox: on search styles and tactics. Health Information & Libraries Journal. 2008;25(4):313–7.

Article   Google Scholar  

Petticrew M, Roberts H. Systematic reviews in the social sciences: a practical guide. Oxford: Blackwell Publishing Ltd; 2006.

Book   Google Scholar  

Institute for Quality and Efficiency in Health Care (IQWiG). IQWiG Methods Resources. 7 Information retrieval 2014 [Available from: https://www.ncbi.nlm.nih.gov/books/NBK385787/ .

NICE: National Institute for Health and Care Excellence. Developing NICE guidelines: the manual 2014. Available from: https://www.nice.org.uk/media/default/about/what-we-do/our-programmes/developing-nice-guidelines-the-manual.pdf .

Sampson M. MJ, Lefebvre C, Moher D, Grimshaw J. Peer Review of Electronic Search Strategies: PRESS; 2008.

Google Scholar  

Centre for Reviews & Dissemination. Systematic reviews – CRD’s guidance for undertaking reviews in healthcare. York: Centre for Reviews and Dissemination, University of York; 2009.

eunetha: European Network for Health Technology Assesment Process of information retrieval for systematic reviews and health technology assessments on clinical effectiveness 2016. Available from: http://www.eunethta.eu/sites/default/files/Guideline_Information_Retrieval_V1-1.pdf .

Kugley SWA, Thomas J, Mahood Q, Jørgensen AMK, Hammerstrøm K, Sathe N. Searching for studies: a guide to information retrieval for Campbell systematic reviews. Oslo: Campbell Collaboration. 2017; Available from: https://www.campbellcollaboration.org/library/searching-for-studies-information-retrieval-guide-campbell-reviews.html

Lefebvre C, Manheimer E, Glanville J. Chapter 6: searching for studies. In: JPT H, Green S, editors. Cochrane Handbook for Systematic Reviews of Interventions; 2011.

Collaboration for Environmental Evidence. Guidelines for Systematic Review and Evidence Synthesis in Environmental Management.: Environmental Evidence:; 2013. Available from: http://www.environmentalevidence.org/wp-content/uploads/2017/01/Review-guidelines-version-4.2-final-update.pdf .

The Joanna Briggs Institute. Joanna Briggs institute reviewers’ manual. 2014th ed: the Joanna Briggs institute; 2014. Available from: https://joannabriggs.org/assets/docs/sumari/ReviewersManual-2014.pdf

Beverley CA, Booth A, Bath PA. The role of the information specialist in the systematic review process: a health information case study. Health Inf Libr J. 2003;20(2):65–74.

Article   CAS   Google Scholar  

Harris MR. The librarian's roles in the systematic review process: a case study. Journal of the Medical Library Association. 2005;93(1):81–7.

PubMed   PubMed Central   Google Scholar  

Egger JB. Use of recommended search strategies in systematic reviews and the impact of librarian involvement: a cross-sectional survey of recent authors. PLoS One. 2015;10(5):e0125931.

Li L, Tian J, Tian H, Moher D, Liang F, Jiang T, et al. Network meta-analyses could be improved by searching more sources and by involving a librarian. J Clin Epidemiol. 2014;67(9):1001–7.

Article   PubMed   Google Scholar  

McGowan J, Sampson M. Systematic reviews need systematic searchers. J Med Libr Assoc. 2005;93(1):74–80.

Rethlefsen ML, Farrell AM, Osterhaus Trzasko LC, Brigham TJ. Librarian co-authors correlated with higher quality reported search strategies in general internal medicine systematic reviews. J Clin Epidemiol. 2015;68(6):617–26.

Weller AC. Mounting evidence that librarians are essential for comprehensive literature searches for meta-analyses and Cochrane reports. J Med Libr Assoc. 2004;92(2):163–4.

Swinkels A, Briddon J, Hall J. Two physiotherapists, one librarian and a systematic literature review: collaboration in action. Health Info Libr J. 2006;23(4):248–56.

Foster M. An overview of the role of librarians in systematic reviews: from expert search to project manager. EAHIL. 2015;11(3):3–7.

Lawson L. OPERATING OUTSIDE LIBRARY WALLS 2004.

Vassar M, Yerokhin V, Sinnett PM, Weiher M, Muckelrath H, Carr B, et al. Database selection in systematic reviews: an insight through clinical neurology. Health Inf Libr J. 2017;34(2):156–64.

Townsend WA, Anderson PF, Ginier EC, MacEachern MP, Saylor KM, Shipman BL, et al. A competency framework for librarians involved in systematic reviews. Journal of the Medical Library Association : JMLA. 2017;105(3):268–75.

Cooper ID, Crum JA. New activities and changing roles of health sciences librarians: a systematic review, 1990-2012. Journal of the Medical Library Association : JMLA. 2013;101(4):268–77.

Crum JA, Cooper ID. Emerging roles for biomedical librarians: a survey of current practice, challenges, and changes. Journal of the Medical Library Association : JMLA. 2013;101(4):278–86.

Dudden RF, Protzko SL. The systematic review team: contributions of the health sciences librarian. Med Ref Serv Q. 2011;30(3):301–15.

Golder S, Loke Y, McIntosh HM. Poor reporting and inadequate searches were apparent in systematic reviews of adverse effects. J Clin Epidemiol. 2008;61(5):440–8.

Maggio LA, Tannery NH, Kanter SL. Reproducibility of literature search reporting in medical education reviews. Academic medicine : journal of the Association of American Medical Colleges. 2011;86(8):1049–54.

Meert D, Torabi N, Costella J. Impact of librarians on reporting of the literature searching component of pediatric systematic reviews. Journal of the Medical Library Association : JMLA. 2016;104(4):267–77.

Morris M, Boruff JT, Gore GC. Scoping reviews: establishing the role of the librarian. Journal of the Medical Library Association : JMLA. 2016;104(4):346–54.

Koffel JB, Rethlefsen ML. Reproducibility of search strategies is poor in systematic reviews published in high-impact pediatrics, cardiology and surgery journals: a cross-sectional study. PLoS One. 2016;11(9):e0163309.

Article   PubMed   PubMed Central   CAS   Google Scholar  

Fehrmann P, Thomas J. Comprehensive computer searches and reporting in systematic reviews. Research Synthesis Methods. 2011;2(1):15–32.

Booth A. Searching for qualitative research for inclusion in systematic reviews: a structured methodological review. Systematic Reviews. 2016;5(1):74.

Article   PubMed   PubMed Central   Google Scholar  

Egger M, Juni P, Bartlett C, Holenstein F, Sterne J. How important are comprehensive literature searches and the assessment of trial quality in systematic reviews? Empirical study. Health technology assessment (Winchester, England). 2003;7(1):1–76.

Tricco AC, Tetzlaff J, Sampson M, Fergusson D, Cogo E, Horsley T, et al. Few systematic reviews exist documenting the extent of bias: a systematic review. J Clin Epidemiol. 2008;61(5):422–34.

Booth A. How much searching is enough? Comprehensive versus optimal retrieval for technology assessments. Int J Technol Assess Health Care. 2010;26(4):431–5.

Papaioannou D, Sutton A, Carroll C, Booth A, Wong R. Literature searching for social science systematic reviews: consideration of a range of search techniques. Health Inf Libr J. 2010;27(2):114–22.

Petticrew M. Time to rethink the systematic review catechism? Moving from ‘what works’ to ‘what happens’. Systematic Reviews. 2015;4(1):36.

Betrán AP, Say L, Gülmezoglu AM, Allen T, Hampson L. Effectiveness of different databases in identifying studies for systematic reviews: experience from the WHO systematic review of maternal morbidity and mortality. BMC Med Res Methodol. 2005;5

Felson DT. Bias in meta-analytic research. J Clin Epidemiol. 1992;45(8):885–92.

Article   PubMed   CAS   Google Scholar  

Franco A, Malhotra N, Simonovits G. Publication bias in the social sciences: unlocking the file drawer. Science. 2014;345(6203):1502–5.

Hartling L, Featherstone R, Nuspl M, Shave K, Dryden DM, Vandermeer B. Grey literature in systematic reviews: a cross-sectional study of the contribution of non-English reports, unpublished studies and dissertations to the results of meta-analyses in child-relevant reviews. BMC Med Res Methodol. 2017;17(1):64.

Schmucker CM, Blümle A, Schell LK, Schwarzer G, Oeller P, Cabrera L, et al. Systematic review finds that study data not published in full text articles have unclear impact on meta-analyses results in medical research. PLoS One. 2017;12(4):e0176210.

Egger M, Zellweger-Zahner T, Schneider M, Junker C, Lengeler C, Antes G. Language bias in randomised controlled trials published in English and German. Lancet (London, England). 1997;350(9074):326–9.

Moher D, Pham B, Lawson ML, Klassen TP. The inclusion of reports of randomised trials published in languages other than English in systematic reviews. Health technology assessment (Winchester, England). 2003;7(41):1–90.

Pham B, Klassen TP, Lawson ML, Moher D. Language of publication restrictions in systematic reviews gave different results depending on whether the intervention was conventional or complementary. J Clin Epidemiol. 2005;58(8):769–76.

Mills EJ, Kanters S, Thorlund K, Chaimani A, Veroniki A-A, Ioannidis JPA. The effects of excluding treatments from network meta-analyses: survey. BMJ : British Medical Journal. 2013;347

Hartling L, Featherstone R, Nuspl M, Shave K, Dryden DM, Vandermeer B. The contribution of databases to the results of systematic reviews: a cross-sectional study. BMC Med Res Methodol. 2016;16(1):127.

van Driel ML, De Sutter A, De Maeseneer J, Christiaens T. Searching for unpublished trials in Cochrane reviews may not be worth the effort. J Clin Epidemiol. 2009;62(8):838–44.e3.

Buchberger B, Krabbe L, Lux B, Mattivi JT. Evidence mapping for decision making: feasibility versus accuracy - when to abandon high sensitivity in electronic searches. German medical science : GMS e-journal. 2016;14:Doc09.

Lorenc T, Pearson M, Jamal F, Cooper C, Garside R. The role of systematic reviews of qualitative evidence in evaluating interventions: a case study. Research Synthesis Methods. 2012;3(1):1–10.

Gough D. Weight of evidence: a framework for the appraisal of the quality and relevance of evidence. Res Pap Educ. 2007;22(2):213–28.

Barroso J, Gollop CJ, Sandelowski M, Meynell J, Pearce PF, Collins LJ. The challenges of searching for and retrieving qualitative studies. West J Nurs Res. 2003;25(2):153–78.

Britten N, Garside R, Pope C, Frost J, Cooper C. Asking more of qualitative synthesis: a response to Sally Thorne. Qual Health Res. 2017;27(9):1370–6.

Booth A, Carroll C. Systematic searching for theory to inform systematic reviews: is it feasible? Is it desirable? Health Info Libr J. 2015;32(3):220–35.

Kwon Y, Powelson SE, Wong H, Ghali WA, Conly JM. An assessment of the efficacy of searching in biomedical databases beyond MEDLINE in identifying studies for a systematic review on ward closures as an infection control intervention to control outbreaks. Syst Rev. 2014;3:135.

Nussbaumer-Streit B, Klerings I, Wagner G, Titscher V, Gartlehner G. Assessing the validity of abbreviated literature searches for rapid reviews: protocol of a non-inferiority and meta-epidemiologic study. Systematic Reviews. 2016;5:197.

Wagner G, Nussbaumer-Streit B, Greimel J, Ciapponi A, Gartlehner G. Trading certainty for speed - how much uncertainty are decisionmakers and guideline developers willing to accept when using rapid reviews: an international survey. BMC Med Res Methodol. 2017;17(1):121.

Ogilvie D, Hamilton V, Egan M, Petticrew M. Systematic reviews of health effects of social interventions: 1. Finding the evidence: how far should you go? J Epidemiol Community Health. 2005;59(9):804–8.

Royle P, Milne R. Literature searching for randomized controlled trials used in Cochrane reviews: rapid versus exhaustive searches. Int J Technol Assess Health Care. 2003;19(4):591–603.

Pearson M, Moxham T, Ashton K. Effectiveness of search strategies for qualitative research about barriers and facilitators of program delivery. Eval Health Prof. 2011;34(3):297–308.

Levay P, Raynor M, Tuvey D. The Contributions of MEDLINE, Other Bibliographic Databases and Various Search Techniques to NICE Public Health Guidance. 2015. 2015;10(1):19.

Nussbaumer-Streit B, Klerings I, Wagner G, Heise TL, Dobrescu AI, Armijo-Olivo S, et al. Abbreviated literature searches were viable alternatives to comprehensive searches: a meta-epidemiological study. J Clin Epidemiol. 2018;102:1–11.

Briscoe S, Cooper C, Glanville J, Lefebvre C. The loss of the NHS EED and DARE databases and the effect on evidence synthesis and evaluation. Res Synth Methods. 2017;8(3):256–7.

Stansfield C, O'Mara-Eves A, Thomas J. Text mining for search term development in systematic reviewing: A discussion of some methods and challenges. Research Synthesis Methods.n/a-n/a.

Petrova M, Sutcliffe P, Fulford KW, Dale J. Search terms and a validated brief search filter to retrieve publications on health-related values in Medline: a word frequency analysis study. Journal of the American Medical Informatics Association : JAMIA. 2012;19(3):479–88.

Stansfield C, Thomas J, Kavanagh J. 'Clustering' documents automatically to support scoping reviews of research: a case study. Res Synth Methods. 2013;4(3):230–41.

PubMed   Google Scholar  

Methley AM, Campbell S, Chew-Graham C, McNally R, Cheraghi-Sohi S. PICO, PICOS and SPIDER: a comparison study of specificity and sensitivity in three search tools for qualitative systematic reviews. BMC Health Serv Res. 2014;14:579.

Andrew B. Clear and present questions: formulating questions for evidence based practice. Library Hi Tech. 2006;24(3):355–68.

Cooke A, Smith D, Booth A. Beyond PICO: the SPIDER tool for qualitative evidence synthesis. Qual Health Res. 2012;22(10):1435–43.

Whiting P, Westwood M, Bojke L, Palmer S, Richardson G, Cooper J, et al. Clinical effectiveness and cost-effectiveness of tests for the diagnosis and investigation of urinary tract infection in children: a systematic review and economic model. Health technology assessment (Winchester, England). 2006;10(36):iii-iv, xi-xiii, 1–154.

Cooper C, Levay P, Lorenc T, Craig GM. A population search filter for hard-to-reach populations increased search efficiency for a systematic review. J Clin Epidemiol. 2014;67(5):554–9.

Hausner E, Waffenschmidt S, Kaiser T, Simon M. Routine development of objectively derived search strategies. Systematic Reviews. 2012;1(1):19.

Hausner E, Guddat C, Hermanns T, Lampert U, Waffenschmidt S. Prospective comparison of search strategies for systematic reviews: an objective approach yielded higher sensitivity than a conceptual one. J Clin Epidemiol. 2016;77:118–24.

Craven J, Levay P. Recording database searches for systematic reviews - what is the value of adding a narrative to peer-review checklists? A case study of nice interventional procedures guidance. Evid Based Libr Inf Pract. 2011;6(4):72–87.

Wright K, Golder S, Lewis-Light K. What value is the CINAHL database when searching for systematic reviews of qualitative studies? Syst Rev. 2015;4:104.

Beckles Z, Glover S, Ashe J, Stockton S, Boynton J, Lai R, et al. Searching CINAHL did not add value to clinical questions posed in NICE guidelines. J Clin Epidemiol. 2013;66(9):1051–7.

Cooper C, Rogers M, Bethel A, Briscoe S, Lowe J. A mapping review of the literature on UK-focused health and social care databases. Health Inf Libr J. 2015;32(1):5–22.

Younger P, Boddy K. When is a search not a search? A comparison of searching the AMED complementary health database via EBSCOhost, OVID and DIALOG. Health Inf Libr J. 2009;26(2):126–35.

Lam MT, McDiarmid M. Increasing number of databases searched in systematic reviews and meta-analyses between 1994 and 2014. Journal of the Medical Library Association : JMLA. 2016;104(4):284–9.

Bethel A, editor Search summary tables for systematic reviews: results and findings. HLC Conference 2017a.

Aagaard T, Lund H, Juhl C. Optimizing literature search in systematic reviews - are MEDLINE, EMBASE and CENTRAL enough for identifying effect studies within the area of musculoskeletal disorders? BMC Med Res Methodol. 2016;16(1):161.

Adams CE, Frederick K. An investigation of the adequacy of MEDLINE searches for randomized controlled trials (RCTs) of the effects of mental health care. Psychol Med. 1994;24(3):741–8.

Kelly L, St Pierre-Hansen N. So many databases, such little clarity: searching the literature for the topic aboriginal. Canadian family physician Medecin de famille canadien. 2008;54(11):1572–3.

Lawrence DW. What is lost when searching only one literature database for articles relevant to injury prevention and safety promotion? Injury Prevention. 2008;14(6):401–4.

Lemeshow AR, Blum RE, Berlin JA, Stoto MA, Colditz GA. Searching one or two databases was insufficient for meta-analysis of observational studies. J Clin Epidemiol. 2005;58(9):867–73.

Sampson M, Barrowman NJ, Moher D, Klassen TP, Pham B, Platt R, et al. Should meta-analysts search Embase in addition to Medline? J Clin Epidemiol. 2003;56(10):943–55.

Stevinson C, Lawlor DA. Searching multiple databases for systematic reviews: added value or diminishing returns? Complementary Therapies in Medicine. 2004;12(4):228–32.

Suarez-Almazor ME, Belseck E, Homik J, Dorgan M, Ramos-Remus C. Identifying clinical trials in the medical literature with electronic databases: MEDLINE alone is not enough. Control Clin Trials. 2000;21(5):476–87.

Taylor B, Wylie E, Dempster M, Donnelly M. Systematically retrieving research: a case study evaluating seven databases. Res Soc Work Pract. 2007;17(6):697–706.

Beyer FR, Wright K. Can we prioritise which databases to search? A case study using a systematic review of frozen shoulder management. Health Info Libr J. 2013;30(1):49–58.

Duffy S, de Kock S, Misso K, Noake C, Ross J, Stirk L. Supplementary searches of PubMed to improve currency of MEDLINE and MEDLINE in-process searches via Ovid. Journal of the Medical Library Association : JMLA. 2016;104(4):309–12.

Katchamart W, Faulkner A, Feldman B, Tomlinson G, Bombardier C. PubMed had a higher sensitivity than Ovid-MEDLINE in the search for systematic reviews. J Clin Epidemiol. 2011;64(7):805–7.

Cooper C, Lovell R, Husk K, Booth A, Garside R. Supplementary search methods were more effective and offered better value than bibliographic database searching: a case study from public health and environmental enhancement (in Press). Research Synthesis Methods. 2017;

Cooper C, Booth, A., Britten, N., Garside, R. A comparison of results of empirical studies of supplementary search techniques and recommendations in review methodology handbooks: A methodological review. (In Press). BMC Systematic Reviews. 2017.

Greenhalgh T, Peacock R. Effectiveness and efficiency of search methods in systematic reviews of complex evidence: audit of primary sources. BMJ (Clinical research ed). 2005;331(7524):1064–5.

Article   PubMed Central   Google Scholar  

Hinde S, Spackman E. Bidirectional citation searching to completion: an exploration of literature searching methods. PharmacoEconomics. 2015;33(1):5–11.

Levay P, Ainsworth N, Kettle R, Morgan A. Identifying evidence for public health guidance: a comparison of citation searching with web of science and Google scholar. Res Synth Methods. 2016;7(1):34–45.

McManus RJ, Wilson S, Delaney BC, Fitzmaurice DA, Hyde CJ, Tobias RS, et al. Review of the usefulness of contacting other experts when conducting a literature search for systematic reviews. BMJ (Clinical research ed). 1998;317(7172):1562–3.

Westphal A, Kriston L, Holzel LP, Harter M, von Wolff A. Efficiency and contribution of strategies for finding randomized controlled trials: a case study from a systematic review on therapeutic interventions of chronic depression. Journal of public health research. 2014;3(2):177.

Matthews EJ, Edwards AG, Barker J, Bloor M, Covey J, Hood K, et al. Efficient literature searching in diffuse topics: lessons from a systematic review of research on communicating risk to patients in primary care. Health Libr Rev. 1999;16(2):112–20.

Bethel A. Endnote Training (YouTube Videos) 2017b [Available from: http://medicine.exeter.ac.uk/esmi/workstreams/informationscience/is_resources,_guidance_&_advice/ .

Bramer WM, Giustini D, de Jonge GB, Holland L, Bekhuis T. De-duplication of database search results for systematic reviews in EndNote. Journal of the Medical Library Association : JMLA. 2016;104(3):240–3.

Bramer WM, Milic J, Mast F. Reviewing retrieved references for inclusion in systematic reviews using EndNote. Journal of the Medical Library Association : JMLA. 2017;105(1):84–7.

Gall C, Brahmi FA. Retrieval comparison of EndNote to search MEDLINE (Ovid and PubMed) versus searching them directly. Medical reference services quarterly. 2004;23(3):25–32.

Ahmed KK, Al Dhubaib BE. Zotero: a bibliographic assistant to researcher. J Pharmacol Pharmacother. 2011;2(4):303–5.

Coar JT, Sewell JP. Zotero: harnessing the power of a personal bibliographic manager. Nurse Educ. 2010;35(5):205–7.

Moher D, Liberati A, Tetzlaff J, Altman DG, The PG. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med. 2009;6(7):e1000097.

Sampson M, McGowan J, Tetzlaff J, Cogo E, Moher D. No consensus exists on search reporting methods for systematic reviews. J Clin Epidemiol. 2008;61(8):748–54.

Toews LC. Compliance of systematic reviews in veterinary journals with preferred reporting items for systematic reviews and meta-analysis (PRISMA) literature search reporting guidelines. Journal of the Medical Library Association : JMLA. 2017;105(3):233–9.

Booth A. "brimful of STARLITE": toward standards for reporting literature searches. Journal of the Medical Library Association : JMLA. 2006;94(4):421–9. e205

Faggion CM Jr, Wu YC, Tu YK, Wasiak J. Quality of search strategies reported in systematic reviews published in stereotactic radiosurgery. Br J Radiol. 2016;89(1062):20150878.

Mullins MM, DeLuca JB, Crepaz N, Lyles CM. Reporting quality of search methods in systematic reviews of HIV behavioral interventions (2000–2010): are the searches clearly explained, systematic and reproducible? Research Synthesis Methods. 2014;5(2):116–30.

Yoshii A, Plaut DA, McGraw KA, Anderson MJ, Wellik KE. Analysis of the reporting of search strategies in Cochrane systematic reviews. Journal of the Medical Library Association : JMLA. 2009;97(1):21–9.

Bigna JJ, Um LN, Nansseu JR. A comparison of quality of abstracts of systematic reviews including meta-analysis of randomized controlled trials in high-impact general medicine journals before and after the publication of PRISMA extension for abstracts: a systematic review and meta-analysis. Syst Rev. 2016;5(1):174.

Akhigbe T, Zolnourian A, Bulters D. Compliance of systematic reviews articles in brain arteriovenous malformation with PRISMA statement guidelines: review of literature. Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia. 2017;39:45–8.

Tao KM, Li XQ, Zhou QH, Moher D, Ling CQ, Yu WF. From QUOROM to PRISMA: a survey of high-impact medical journals' instructions to authors and a review of systematic reviews in anesthesia literature. PLoS One. 2011;6(11):e27611.

Wasiak J, Tyack Z, Ware R. Goodwin N. Jr. Poor methodological quality and reporting standards of systematic reviews in burn care management. International wound journal: Faggion CM; 2016.

Tam WW, Lo KK, Khalechelvam P. Endorsement of PRISMA statement and quality of systematic reviews and meta-analyses published in nursing journals: a cross-sectional study. BMJ Open. 2017;7(2):e013905.

Rader T, Mann M, Stansfield C, Cooper C, Sampson M. Methods for documenting systematic review searches: a discussion of common issues. Res Synth Methods. 2014;5(2):98–115.

Atkinson KM, Koenka AC, Sanchez CE, Moshontz H, Cooper H. Reporting standards for literature searches and report inclusion criteria: making research syntheses more transparent and easy to replicate. Res Synth Methods. 2015;6(1):87–95.

McGowan J, Sampson M, Salzwedel DM, Cogo E, Foerster V, Lefebvre C. PRESS peer review of electronic search strategies: 2015 guideline statement. J Clin Epidemiol. 2016;75:40–6.

Sampson M, McGowan J, Cogo E, Grimshaw J, Moher D, Lefebvre C. An evidence-based practice guideline for the peer review of electronic search strategies. J Clin Epidemiol. 2009;62(9):944–52.

Shea BJ, Reeves BC, Wells G, Thuku M, Hamel C, Moran J, et al. AMSTAR 2: a critical appraisal tool for systematic reviews that include randomised or non-randomised studies of healthcare interventions, or both. BMJ (Clinical research ed). 2017;358.

Whiting P, Savović J, Higgins JPT, Caldwell DM, Reeves BC, Shea B, et al. ROBIS: a new tool to assess risk of bias in systematic reviews was developed. J Clin Epidemiol. 2016;69:225–34.

Relevo R, Balshem H. Finding evidence for comparing medical interventions: AHRQ and the effective health care program. J Clin Epidemiol. 2011;64(11):1168–77.

Medicine Io. Standards for Systematic Reviews 2011 [Available from: http://www.nationalacademies.org/hmd/Reports/2011/Finding-What-Works-in-Health-Care-Standards-for-Systematic-Reviews/Standards.aspx .

CADTH: Resources 2018.

Download references

Acknowledgements

CC acknowledges the supervision offered by Professor Chris Hyde.

This publication forms a part of CC’s PhD. CC’s PhD was funded through the National Institute for Health Research (NIHR) Health Technology Assessment (HTA) Programme (Project Number 16/54/11). The open access fee for this publication was paid for by Exeter Medical School.

RG and NB were partially supported by the National Institute for Health Research (NIHR) Collaboration for Leadership in Applied Health Research and Care South West Peninsula.

The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health.

Author information

Authors and affiliations.

Institute of Health Research, University of Exeter Medical School, Exeter, UK

Chris Cooper & Jo Varley-Campbell

HEDS, School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK

Andrew Booth

Nicky Britten

European Centre for Environment and Human Health, University of Exeter Medical School, Truro, UK

Ruth Garside

You can also search for this author in PubMed   Google Scholar

Contributions

CC conceived the idea for this study and wrote the first draft of the manuscript. CC discussed this publication in PhD supervision with AB and separately with JVC. CC revised the publication with input and comments from AB, JVC, RG and NB. All authors revised the manuscript prior to submission. All authors read and approved the final manuscript.

Corresponding author

Correspondence to Chris Cooper .

Ethics declarations

Ethics approval and consent to participate, consent for publication, competing interests.

The authors declare that they have no competing interests.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Additional file

Additional file 1:.

Appendix tables and PubMed search strategy. Key studies used for pearl growing per key stage, working data extraction tables and the PubMed search strategy. (DOCX 30 kb)

Rights and permissions

Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License ( http://creativecommons.org/licenses/by/4.0/ ), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver ( http://creativecommons.org/publicdomain/zero/1.0/ ) applies to the data made available in this article, unless otherwise stated.

Reprints and permissions

About this article

Cite this article.

Cooper, C., Booth, A., Varley-Campbell, J. et al. Defining the process to literature searching in systematic reviews: a literature review of guidance and supporting studies. BMC Med Res Methodol 18 , 85 (2018). https://doi.org/10.1186/s12874-018-0545-3

Download citation

Received : 20 September 2017

Accepted : 06 August 2018

Published : 14 August 2018

DOI : https://doi.org/10.1186/s12874-018-0545-3

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

• Literature Search Process
• Citation Chasing
• Tacit Models
• Unique Guidance
• Information Specialists

BMC Medical Research Methodology

ISSN: 1471-2288

• General enquiries: [email protected]

Literature Reviews

• Getting started

What is a literature review?

Why conduct a literature review, stages of a literature review, lit reviews: an overview (video), check out these books.

• Types of reviews
• 1. Define your research question
• 2. Plan your search
• 3. Search the literature
• 4. Organize your results
• 5. Synthesize your findings
• 6. Write the review
• Artificial intelligence (AI) tools
• Thompson Writing Studio This link opens in a new window
• Need to write a systematic review? This link opens in a new window

Guide Owner

Contact a Librarian

Ask a Librarian

Definition: A literature review is a systematic examination and synthesis of existing scholarly research on a specific topic or subject.

Purpose: It serves to provide a comprehensive overview of the current state of knowledge within a particular field.

Analysis: Involves critically evaluating and summarizing key findings, methodologies, and debates found in academic literature.

Identifying Gaps: Aims to pinpoint areas where there is a lack of research or unresolved questions, highlighting opportunities for further investigation.

Contextualization: Enables researchers to understand how their work fits into the broader academic conversation and contributes to the existing body of knowledge.

tl;dr  A literature review critically examines and synthesizes existing scholarly research and publications on a specific topic to provide a comprehensive understanding of the current state of knowledge in the field.

What is a literature review NOT?

❌ An annotated bibliography

❌ Original research

❌ A summary

❌ Something to be conducted at the end of your research

❌ An opinion piece

❌ A chronological compilation of studies

The reason for conducting a literature review is to:

Literature Reviews: An Overview for Graduate Students

While this 9-minute video from NCSU is geared toward graduate students, it is useful for anyone conducting a literature review.

Writing the literature review: A practical guide

Available 3rd floor of Perkins

Writing literature reviews: A guide for students of the social and behavioral sciences

Available online!

So, you have to write a literature review: A guided workbook for engineers

Telling a research story: Writing a literature review

The literature review: Six steps to success

Systematic approaches to a successful literature review

Request from Duke Medical Center Library

Doing a systematic review: A student's guide

• Next: Types of reviews >>
• Last Updated: Aug 20, 2024 3:37 PM
• URL: https://guides.library.duke.edu/litreviews

Services for...

• Faculty & Instructors
• Graduate Students
• Undergraduate Students
• International Students
• Patrons with Disabilities

• Harmful Language Statement
• Re-use & Attribution / Privacy
• Support the Libraries

A systematic review of micro-texture formation based on milling: from mechanism, existing techniques, characterization to typical applications

• Critical Review
• Published: 27 August 2024

Cite this article

• Zhiwen Jiang 1 , 2 ,
• Dongju Chen 1 , 2 ,
• Kun Sun 1 , 2 ,
• Ri Pan 1 , 2 ,
• Jinwei Fan 1 , 2 &
• Yuhang Tang 3  

Milling-based micro-texturing is an emerging technique that employs mechanical milling to create precise and flexible surface patterns, enabling controlled surface property modulation. With high precision, controllability, repeatability, and mass production, it finds extensive applications in optics, biomedical engineering, mechanical engineering, and among others. Herein, this paper systematically summarizes the key contents of micro-texturing technology from the perspective of mechanical milling for the first time. Firstly, the surface texture generation mechanisms are systematically described, encompassing milling forces modeling, texture formation process, and size effect. Secondly, the importance of tool selection and manufacturing in micro-milling is briefly addressed, followed by a detailed classification and comparison of existing milling-based micro-texturing techniques for metallic and non-metallic materials. Subsequently, the design criteria of surface micro-texturing, methods for characterizing its performance, and typical applications of this technology are summarized in detail. Finally, a brief summary and outlook for future work are delineated. This research is expected to facilitate the enhancement of surface performance, the development of functional materials, and the exploration of novel applications in response to ultra-precision manufacturing demands.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Subscribe and save.

• Get 10 units per month
• Download Article/Chapter or eBook
• 1 Unit = 1 Article or 1 Chapter
• Cancel anytime

Price includes VAT (Russian Federation)

Instant access to the full article PDF.

Rent this article via DeepDyve

Institutional subscriptions

Explore related subjects

Zhang Q, Wang Q, Zhang Z, Fu Y, Xu J (2022) Surface micro-texture on sapphire fabricated by laser ablation trajectory regulation. Chin J Aeronaut 35(3):525–536

Article   Google Scholar  

Zhang J, Zhang S, Chen G, Jia Z, Qu Y, Guo Z (2022) Laser micro-texture formation mechanism based on modified heat-mass transfers and hydrodynamic models. Int J Mech Sci 230:107528

Cunha W, Carvalho O, Henriques B, Silva FS, Ozcan M, Souza JCM (2022) Surface modification of zirconia dental implants by laser texturing. Lasers Med Sci 37(1):77–93

Li JZ, Shen FH, Yu ZY, Natsu W (2013) Influence of microstructure of alloy on the machining performance of micro EDM. Surf Coat Technol 228:S460–S465

Zheng Z-P, Cheng W-H, Huang F-Y, Yan B-H (2007) 3D microstructuring of Pyrex glass using the electrochemical discharge machining process. J Micromech Microeng 17(5):960–966

Xu S, Shimada K, Mizutani M, Kuriyagawa T (2014) Fabrication of hybrid micro/nano-textured surfaces using rotary ultrasonic machining with one-point diamond tool. Int J Mach Tools Manuf 86:12–17

Zhang S, Zhou Y, Zhang H, Xiong Z, To S (2019) Advances in ultra-precision machining of micro-structured functional surfaces and their typical applications. Int J Mach Tools Manuf 142:16–41

Kim J, Lee S-K (2016) Micro-patterning technique using a rotating cutting tool controlled by an electromagnetic actuator. Int J Mach Tools Manuf 101:52–64

Kim GD, Loh BG (2013) Cutting force variation with respect to tilt angle of trajectory in elliptical vibration V-grooving. Int J Precis Eng Manuf 14(10):1861–1864

Kim GD, Loh BG (2011) Direct machining of micro patterns on nickel alloy and mold steel by vibration assisted cutting. Int J Precis Eng Manuf 12(4):583–588

Grazia Guerra M, Lavecchia F (2023) Measurement of additively manufactured freeform artefacts: the influence of surface texture on measurements carried out with optical techniques. Measurement 209:112540

Zheng Y, Zhao H, Cai Y, Jurado-Sanchez B, Dong R (2022) Recent advances in one-dimensional micro/nanomotors: fabrication, propulsion and application. Nano Lett 15(1):20

Lipovsek B, Krc J, Topic M (2018) Microtextured light-management foils and their optimization for planar organic and perovskite solar cells. IEEE J Photovolt 8(3):783–792

Aurich JC, Reichenbach IG, Schüler GM (2012) Manufacture and application of ultra-small micro end mills. CIRP Ann 61(1):83–86

Chen W, Zheng L, Xie W, Yang K, Huo D (2019) Modelling and experimental investigation on textured surface generation in vibration-assisted micro-milling. J Mater Process Technol 266:339–350

Pratap T, Patra K (2020) Tribological performances of symmetrically micro-textured Ti-6Al-4V alloy for hip joint. Int J Mech Sci 182:105736

Han J, Hao X, Li L, Liu L, Chen N, Zhao G, He N (2020) Investigation on surface quality and burr generation of high aspect ratio (HAR) micro-milled grooves. J Manuf Process 52:35–43

Greco S, Kieren-Ehses S, Kirsch B, Aurich JC (2020) Micro milling of additively manufactured AISI 316L: impact of the layerwise microstructure on the process results. Int J Adv Manuf Technol 112(1-2):361–373

Tillmann W, Hagen L, Stangier D, Paulus M, Tolan M, Sakrowski R, Biermann D, Freiburg D (2019) Microstructural characteristics of high-feed milled HVOF sprayed WC-Co coatings. Surf Coat Technol 374:448–459

Zhang X, Ehmann KF, Yu T, Wang W (2016) Cutting forces in micro-end-milling processes. Int J Mach Tools Manuf 107:21–40

Sun Q, Zhou J, Li P (2022) Simulations and experiments on the micro-milling process of a thin-walled structure of Al6061-T6. Materials 15(10):3568

Fu MW, Wang JL (2021) Size effects in multi-scale materials processing and manufacturing. Int J Mach Tools Manuf 167:103755

de Oliveira FB, Rodrigues AR, Coelho RT, de Souza AF (2015) Size effect and minimum chip thickness in micromilling. Int J Mach Tools Manuf 89:39–54

Attanasio A, Gelfi M, Pola A, Ceretti E, Giardini C (2013) Influence of material microstructures in micromilling of Ti6Al4V alloy. Materials 6(9):4268–4283

Chen MJ, Ni HB, Wang ZJ, Jiang Y (2012) Research on the modeling of burr formation process in micro-ball end milling operation on Ti–6Al–4V. Int J Adv Manuf Technol 62(9-12):901–912

Baumann J, Krebs E, Biermann D (2019) Chatter avoidance in milling by using advanced cutting tools with structured functional surfaces. MM Sci J 2019(04):3019–3026

Gao Q, Li W, Chen X (2019) Surface quality and tool wear in micro-milling of single-crystal aluminum. Proc Inst Mech Eng C J Mech Eng Sci 233(16):5597–5609

Yuan Y, Jing X, Ehmann KF, Cao J, Li H, Zhang D (2018) Modeling of cutting forces in micro end-milling. J Manuf Process 31:844–858

Yuan Y, Zhang D, Jing X, Cao J, Ehmann KF (2019) Micro texture fabrication by a non-resonant vibration generator. J Manuf Process 45:732–745

He J, Guo Z, Lian H, Wang J, Chen X, Liu J (2019) Improving the machining quality of micro structures by using electrophoresis-assisted ultrasonic micromilling machining. Int J Precis Eng Manuf-Green Technol 7(1):151–161

Wang M, Zhang R, Shang Y, Zheng J, Wang X, Xu X (2023) Micro-milling microstructures in air-shielding ultrasonic assisted electrochemical machining. J Manuf Process 97:171–184

Vishnoi M, Kumar P, Murtaza Q (2021) Surface texturing techniques to enhance tribological performance: a review. Surf Interfaces 27:101463

Ronen A, Etsion I, Kligerman Y (2001) Friction-reducing surface-texturing in reciprocating automotive components. Tribol Trans 44(3):359–366

Hsu SM, Jing Y, Zhao F (2015) Self-adaptive surface texture design for friction reduction across the lubrication regimes. Surf Topogr Metrol Properties 4(1):014004

Bhaumik S, Chowdhury D, Batham A, Sehgal U, Ghosh C, Bhattacharya B, Datta S (2020) Analysing the frictional properties of micro dimpled surface created by milling machine under lubricated condition. Tribol Int 146:106260

Vogler MP, DeVor RE, Kapoor SG (2003) Microstructure-level force prediction model for micro-milling of multi-phase materials. ASME Int Mech Eng Congress Expos 125(2):202–209

Google Scholar  

Vogler MP, Kapoor SG, DeVor RE (2004) On the modeling and analysis of machining performance in micro-endmilling, part ii: cutting force prediction. J Manuf Sci Eng 126(4):695–705

Lai X, Li H, Li C, Lin Z, Ni J (2008) Modelling and analysis of micro scale milling considering size effect, micro cutter edge radius and minimum chip thickness. Int J Mach Tool Manu 48(1):1–14

Wan M, Wen D-Y, Zhang W-H, Yang Y (2023) Prediction of cutting forces in flexible micro milling processes by considering the change of instantaneous cutting direction. J Manuf Process 90:180–195

Zhou Y, Tian Y, Jing X, Ehmann KF (2017) A novel instantaneous uncut chip thickness model for mechanistic cutting force model in micro-end-milling. Int J Adv Manuf Technol 93(5-8):2305–2319

Zhang X, Yu T, Wang W (2018) Prediction of cutting forces and instantaneous tool deflection in micro end milling by considering tool run-out. Int J Mech Sci 136:124–133

Zhang X, Yu T, Xu P, Zhao J (2022) In-process stochastic tool wear identification and its application to the improved cutting force modeling of micro milling. Mech Syst Signal Process 164:108233

Zhang Y, Bai Q, Zhang F, Wang P (2022) Calculation and analysis of quasi-dynamic cutting force and specific cutting energy in micro-milling Ti6Al4V. Int J Adv Manuf Technol 120(9-10):6067–6078

Jing X, Lv R, Song B, Xu J, Jaffery SHI, Li H (2021) A novel run-out model based on spatial tool position for micro-milling force prediction. J Manuf Process 68:739–749

Zhou L, Deng B, Peng F, Yang M, Yan R (2020) Semi-analytic modelling of cutting forces in micro ball-end milling of NAK80 steel with wear-varying cutting edge and associated nonlinear process characteristics. Int J Mech Sci 169:105343

Chen N, Li L, Wu J, Qian J, He N, Reynaerts D (2019) Research on the ploughing force in micro milling of soft-brittle crystals. Int J Mech Sci 155:315–322

Zhou L, Peng FY, Yan R, Yao PF, Yang CC, Li B (2015) Analytical modeling and experimental validation of micro end-milling cutting forces considering edge radius and material strengthening effects. Int J Mach Tools Manuf 97:29–41

Xiao X, Zheng K, Liao W (2014) Theoretical model for cutting force in rotary ultrasonic milling of dental zirconia ceramics. Int J Adv Manuf Technol 75(9-12):1263–1277

Jin X, Altintas Y (2012) Prediction of micro-milling forces with finite element method. J Mater Process Technol 212(3):542–552

Thepsonthi T, Özel T (2013) Experimental and finite element simulation based investigations on micro-milling Ti-6Al-4V titanium alloy: effects of cBN coating on tool wear. J Mater Process Technol 213(4):532–542

Thepsonthi T, Özel T (2015) 3-D finite element process simulation of micro-end milling Ti-6Al-4V titanium alloy: experimental validations on chip flow and tool wear. J Mater Process Technol 221:128–145

Bai QS, Yang K, Liang YC, Yang CL, Wang B (2009) Tool runout effects on wear and mechanics behavior in microend milling. J Vac Sci Technol B Microelectron Nanometer Struct 27(3):1566

Pratap T, Patra K, Dyakonov AA (2015) Modeling cutting force in micro-milling of Ti-6Al-4V titanium alloy. Procedia Eng 129:134–139

Attanasio A, Abeni A, Özel T, Ceretti E (2018) Finite element simulation of high speed micro milling in the presence of tool run-out with experimental validations. Int J Adv Manuf Technol 100(1-4):25–35

Li H, Wu B (2016) Development of a hybrid cutting force model for micromilling of brass. Int J Mech Sci 115-116:586–595

Sahoo P, Pratap T, Patra K (2019) A hybrid modelling approach towards prediction of cutting forces in micro end milling of Ti-6Al-4V titanium alloy. Int J Mech Sci 150:495–509

Sahoo P, Patra K, Singh VK, Gupta MK, Song Q, Mia M, Pimenov DY (2020) Influences of TiAlN coating and limiting angles of flutes on prediction of cutting forces and dynamic stability in micro milling of die steel (P-20). J Mater Process Technol 278:116500

Liu H, Xu X, Zhang J, Liu Z, He Y, Zhao W, Liu Z (2022) The state of the art for numerical simulations of the effect of the microstructure and its evolution in the metal-cutting processes. Int J Mach Tools Manuf 177:103890

Wu Y, Chen N, Bian R, He N, Li Z, Li L (2020) Investigations on burr formation mechanisms in micro milling of high-aspect-ratio titanium alloy ti-6al-4 v structures. Int J Mech Sci 185:105884

Rahman MA, Amrun MR, Rahman M, Kumar AS (2017) Variation of surface generation mechanisms in ultra-precision machining due to relative tool sharpness (RTS) and material properties. Int J Mach Tools Manuf 115:15–28

Ji H, Song Q, Du Y, Zhao Y, Liu Z (2022) Grain-scale material removal mechanisms of crystalline material micro-cutting. Int J Mech Sci 233:107671

Popov KB, Dimov SS, Pham DT, Minev RM, Rosochowski A, Olejnik L (2006) Micromilling: material microstructure effects. Proc Inst Mech Eng B J Eng Manuf 220(11):1807–1813

Han J, Ma R, Kong L, Hao X, Chen N, Li L, He N (2022) Investigation on chip formation mechanism of high-aspect-ratio micro-milled structures. J Manuf Process 80:743–753

Zhang C, Feng P, Zhang J, Wu Z, Yu D (2012) Investigation into the rotary ultrasonic face milling of K9 glass with mechanism study of material removal. Int J Manuf Technol Manag 25(4):248–266

Wang J, Yan Y, Li C, Geng Y (2023) Material removal mechanism and subsurface characteristics of silicon 3D nanomilling. Int J Mech Sci 242:108020

Wang J, Yan Y, Li Z, Geng Y, Luo X, Fan P (2021) Processing outcomes of atomic force microscope tip-based nanomilling with different trajectories on single-crystal silicon. Precis Eng 72:480–490

Aramcharoen A, Mativenga PT (2009) Size effect and tool geometry in micromilling of tool steel. Precis Eng 33(4):402–407

Sahoo P, Patra K, Szalay T, Dyakonov AA (2020) Determination of minimum uncut chip thickness and size effects in micro-milling of P-20 die steel using surface quality and process signal parameters. Int J Adv Manuf Technol 106(11-12):4675–4691

Filiz S, Xie L, Weiss LE, Ozdoganlar OB (2008) Micromilling of microbarbs for medical implants. Int J Mach Tools Manuf 48(3-4):459–472

Arslan A, Masjuki HH, Kalam MA, Varman M, Mufti RA, Mosarof MH, Khuong LS, Quazi MM (2016) Surface texture manufacturing techniques and tribological effect of surface texturing on cutting tool performance: a review. Crit Rev Solid State Mater Sci 41(6):447–481

Boswell B, Islam MN, Davies IJ (2017) A review of micro-mechanical cutting. Int J Adv Manuf Technol 94(1-4):789–806

Sun Y, Gong YD, Wen XL, Yin GQ, Meng FT (2020) Micro milling characteristics of LS-WEDM fabricated helical and corrugated micro end mill. Int J Mech Sci 167:105277

Suzuki H, Okada M, Fujii K, Matsui S, Yamagata Y (2013) Development of micro milling tool made of single crystalline diamond for ceramic cutting. CIRP Ann 62(1):59–62

Chen N, Li HN, Wu J, Li Z, Li L, Liu G, He N (2021) Advances in micro milling: from tool fabrication to process outcomes. Int J Mach Tools Manuf 160:103670

Han J, Hao X, Li L, He N, Zhao G, Chen N (2019) Fabrication of large aspect ratio (LAR) PCD micro-end mill with a hybrid method and performance verification. Int J Adv Manuf Technol 104(1-4):1473–1483

Han J, Ma R, Kong L, He B, Hao X, He Q, Li L, He N (2022) Investigation on self-fabricated PCD cutter and its application in deep-and-narrow micro-grooves. Int J Adv Manuf Technol 119(9-10):6743–6760

Elias JV, Venkatesh NP, Lawrence KD, Mathew J (2020) Tool texturing for micro-turning applications – an approach using mechanical micro indentation. Mater Manuf Process 36(1):84–93

Guo X, Huang Q, Wang C, Liu T, Zhang Y, He H, Zhang K (2022) Effect of magnetic field on cutting performance of micro-textured tools under Fe3O4 nanofluid lubrication condition. J Mater Process Technol 299:117382

Wood RW, Loomis AL (2009) The physical and biological effects of high-frequency sound-waves of great intensity. London Edinburgh Dublin Philos Mag J Sci 4(22):417–436

Mokhtari A, Jalili MM, Mazidi A, Abootorabi MM (2019) Size dependent vibration analysis of micro-milling operations with process damping and structural nonlinearities. Eur J Mech A/Solids 76:57–69

Article   MathSciNet   Google Scholar  

Liu X, Wu D, Zhang J, Hu X, Cui P (2019) Analysis of surface texturing in radial ultrasonic vibration-assisted turning. J Mater Process Technol 267:186–195

Kuo K, Tsao C (2012) Rotary ultrasonic-assisted milling of brittle materials. Trans Nonferrous Metals Soc China 22:s793–s800

Sun L, Zheng K, Liao W, Liu J, Feng J, Dong S (2020) Investigation on chatter stability of robotic rotary ultrasonic milling. Robot Comput Integr Manuf 63:101911

Qin S, Zhu L, Wiercigroch M, Ren T, Hao Y, Ning J, Zhao J (2022) Material removal and surface generation in longitudinal-torsional ultrasonic assisted milling. Int J Mech Sci 227:107375

Shen X-H, Xu G-F (2017) Study of milling force variation in ultrasonic vibration-assisted end milling. Mater Manuf Process 33(6):644–650

Chen W, Zheng L, Huo D, Chen Y (2018) Surface texture formation by non-resonant vibration assisted micro milling. J Micromech Microeng 28(2):025006

Maroju NK, Jin X (2018) Vibration-assisted dimple generation on bulk metallic glass. Procedia Manuf 26:317–328

Li K-M, Wang S-L (2013) Effect of tool wear in ultrasonic vibration-assisted micro-milling. Proc Inst Mech Eng B J Eng Manuf 228(6):847–855

Liu Q, Xu J, Yu H (2020) Experimental study of tool wear and its effects on cutting process of ultrasonic-assisted milling of Ti6Al4V. Int J Adv Manuf Technol 108(9-10):2917–2928

Shen XH, Shi YL, Zhang JH, Zhang QJ, Tao GC, Bai LJ (2020) Effect of process parameters on micro-textured surface generation in feed direction vibration assisted milling. Int J Mech Sci 167:105267

Zheng Z, Zhang J, Feng P, Wang J (2023) Controllable fabrication of microstructures on the metallic surface using oblique rotary ultrasonic milling. Int J Mech Sci 237:107805

Zhang Z, Liu W, Chen X, Zhang Y, Xu C, Wang K, Wang W, Jiang X (2022) Generation mechanism of surface micro-texture in axial ultrasonic vibration-assisted milling (AUVAM). Int J Adv Manuf Technol 122(3-4):1651–1667

Lu H, Zhu L, Yang Z, Lu H, Yan B, Hao Y, Qin S (2021) Research on the generation mechanism and interference of surface texture in ultrasonic vibration assisted milling. Int J Mech Sci 208:106681

Huang F, Jin X (2021) Surface texture generation using high-feed milling with spindle speed modulation. Precis Eng 72:13–24

Amini S, Baraheni M, Khaki M (2021) Empirical study on ultrasonic assisted turn-milling. Proc Inst Mech Eng Part E J Process Mech Eng 235(5):1469–1478

Hao X, Xu W, Chen M, Wang C, Han J, Li L, He N (2021) Laser hybridizing with micro-milling for fabrication of high aspect ratio micro-groove on oxygen-free copper. Precis Eng 70:15–25

Zou X, Jiang B, Wang Z (2023) Laser surface texturing-based hybrid micro-milling of Ti6Al4V alloy. Int J Adv Manuf Technol 125(9-10):4341–4352

Xia H, Zhao G, Zhang Y, Li L, He N, Hansen HN (2022) Nanosecond laser-induced controllable oxidation of TiB2–TiC ceramic composites for subsequent micro milling. Ceram Int 48(2):2470–2481

Nakamoto K, Katahira K, Ohmori H, Yamazaki K, Aoyama T (2012) A study on the quality of micro-machined surfaces on tungsten carbide generated by PCD micro end-milling. CIRP Ann 61(1):567–570

Gao X, Cheng X, Ling S, Zheng G, Li Y, Liu H (2022) Research on optimization of micro-milling process for curved thin wall structure. Precis Eng 73:296–312

Kakinuma Y, Kidani S, Aoyama T (2012) Ultra-precision cryogenic machining of viscoelastic polymers. CIRP Ann 61(1):79–82

Liu Q, Cheng J, Liao Z, Luo X, Yang Y, Li M, Yang H, Tan C, Wang G, Ding W, Yin Z, Zhao L, Chen M (2023) Research on the light intensity modulation and characterizing methods of surface texture on KDP optics generated in fly-cutting and micro ball-end milling processes. CIRP J Manuf Sci Technol 41:30–43

Wang J, Yan Y, Li Z, Geng Y (2021) Towards understanding the machining mechanism of the atomic force microscopy tip-based nanomilling process. Int J Mach Tools Manuf 162:103701

Reichenbach IG, Aurich JC (2014) Application of CAD/CAM and micro end mills with 20 to 120 μm diameter for the direct machining of microstructures in PMMA. Adv Mater Res 907:299–306

Cheng CT, Zhang G, To S (2016) Wetting characteristics of bare micro-patterned cyclic olefin copolymer surfaces fabricated by ultra-precision raster milling. RSC Adv 6(2):1562–1570

Wang G, Yu T, Zhou X, Guo R, Chen M, Sun Y (2023) Material removal mechanism and microstructure fabrication of GDP during micro-milling. Int J Mech Sci 240:107946

Weinert K, Petzoldt V (2008) Machining NiTi micro-parts by micro-milling. Mater Sci Eng A 481-482:672–675

Du H, Wu C, Li D, Yip WS, Wang Z, Ta S (2023) Feasibility study on ultraprecision micro-milling of the additively manufactured NiTi alloy for generating microstructure arrays. J Mater Res Technol 25:55–67

Wan, Y.; Zhang, X.; Yu, Z.; Xu, J.; Yu, H., High speed micro-milling experiment of hydrophobic microstructure 2013 IEEE International Conference on Mechatronics and Automation, Takamatsu, Japan 2013, 174-178.

Shi Z, Liu Z, Song H, Zhang X (2016) Prediction of contact angle for hydrophobic surface fabricated with micro-machining based on minimum Gibbs free energy. Appl Surf Sci 364:597–603

Pratap T, Patra K (2018) Mechanical micro-texturing of Ti-6Al-4V surfaces for improved wettability and bio-tribological performances. Surf Coat Technol 349:71–81

Jain A, Bajpai V (2019) Mechanical micro-texturing and characterization on Ti6Al4V for the improvement of surface properties. Surf Coat Technol 380:125087

Jain A, Kumari N, Jagadevan S, Bajpaia V (2020) Surface properties and bacterial behavior of micro conical dimple textured Ti6Al4V surface through micro-milling. Surf Interfaces 21:100714

Hosseinabadi HN, Sajjady SA, Amini S (2018) Creating micro textured surfaces for the improvement of surface wettability through ultrasonic vibration assisted turning. Int J Adv Manuf Technol 96(5-8):2825–2839

Shen X, Tao G (2015) Tribological behaviors of two micro textured surfaces generated by vibrating milling under boundary lubricated sliding. Int J Adv Manuf Technol 79(9-12):1995–2002

Konneh, M.; Bagum, M. N.; Ali, M. Y.; Amin, A. K. M. N., Surface morphology study in high speed milling of soda lime glass. In 8th International Conference on Nanoscience and Nanotechnology 2017 (Nano-SciTech 2017), 2018; Vol. 1958, p 020005.

Wang J, Wang Y, Yang Y, Yang R, Liao W-H, Guo P (2020) Fabrication of structurally colored basso-relievo with modulated elliptical vibration texturing. Precis Eng 64:113–121

Torta M, Albertelli P, Monno M (2020) Surface morphology prediction model for milling operations. Int J Adv Manuf Technol 106(7-8):3189–3201

Chen P-C, Pan C-W, Lee W-C, Li K-M (2014) Optimization of micromilling microchannels on a polycarbonate substrate. Int J Precis Eng Manuf 15(1):149–154

Yuan W, Li L, Lee W, Chan C (2018) Fabrication of microlens array and its application: a review. Chin J Mech Eng 31(1)

Sun Z, To S, Yu KM (2018) One-step generation of hybrid micro-optics with high-frequency diffractive structures on infrared materials by ultra-precision side milling. Opt Express 26(21):28161–28177

Wang P, Bai Q, Cheng K, Zhao L, Zhang Y (2023) Multi-objective optimization of micro-milling parameters—the trade-offs between machining quality, efficiency, and sustainability in the fabrication of thin-walled microstructures. Appl Sci 13(16)

Zhang Y, Bai Q, Wang P (2023) 3D surface topography analysis and functionality-related performance of the machined surface in slot micro-milling titanium alloy Ti6Al4V. Int J Adv Manuf Technol 127(3-4):1609–1629

Yang Y, Han J, Hao X, Li L, He N (2019) Investigation on micro-milling of micro-grooves with high aspect ratio and laser deburring. Proc Inst Mech Eng B J Eng Manuf 234(5):871–880

Dutterer BS, Lineberger JL, Smilie PJ, Hildebrand DS, Harriman TA, Davies MA, Suleski TJ, Lucca DA (2014) Diamond milling of an Alvarez lens in germanium. Precis Eng 38(2):398–408

Li L, Yi AY (2010) Development of a 3D artificial compound eye. Opt Express 18(17):18125–18137

Ding W, Cao Z, Wang B, Xu S, Wang Z (2019) Construction of grating structure model based on Gibbs free energy and experimental verification by micro-milling. Appl Phys A 125(6):380

Hu P, Lei W, Jiang Y, Huang Y, Song R, Chen H, Dong Y (2018) Development of a 0.32-THz folded waveguide traveling wave tube. IEEE Trans Electron Devices 65(6):2164–2169

Bhardwaj RK, Sudhamani HS, Dutta VP, Bhatnagar N (2021) Micromachining and characterisation of folded waveguide structure at 0.22THz. J Infrared Millim Terahertz Waves 42(3):229–238

Özel T, Biermann D, Enomoto T, Mativenga P (2021) Structured and textured cutting tool surfaces for machining applications. CIRP Ann 70(2):495–518

Wang G, Wan Y, Ren B, Liu Z (2019) Bioactivity of micropatterned TiO(2) nanotubes fabricated by micro-milling and anodic oxidation. Mater Sci Eng C Mater Biol Appl 95:114–121

Lin YS, Yang CH, Wang CY, Chang FR, Huang KS, Hsieh WC (2012) An aluminum microfluidic chip fabrication using a convenient micromilling process for fluorescent poly(DL-lactide-co-glycolide) microparticle generation. Sensors 12(2):1455–1467

Jung YC, Bhushan B (2010) Biomimetic structures for fluid drag reduction in laminar and turbulent flows. J Phys Condens Matter 22(3):035104

Yao C-W, Lai C-L, Alvarado JL, Zhou J, Aung KT, Mejia JE (2017) Experimental study on effect of surface vibration on micro textured surfaces with hydrophobic and hydrophilic materials. Appl Surf Sci 412:45–51

Chakraborty A, Mulroney AT, Gupta MC (2021) Superhydrophobic surfaces by microtexturing: a critical review. Prog Adhes Adhes 6:621–649

Wan Y, Yang J, Yu H (2018) Superhydrophobic surface prepared by micro-milling and WEDM on aluminum alloy. Mater Res Express 5(6):066504

Zhang X, Wan Y, Ren B, Wang H, Yu M, Liu A, Liu Z (2020) Preparation of superhydrophobic surface on titanium alloy via micro-milling, anodic oxidation and fluorination. Micromachines 11(3):316

Pei S, Xu H, Yun M, Shi F, Hong J (2016) Effects of surface texture on the lubrication performance of the floating ring bearing. Tribol Int 102:143–153

Henry Y, Bouyer J, Fillon M (2014) An experimental analysis of the hydrodynamic contribution of textured thrust bearings during steady-state operation: a comparison with the untextured parallel surface configuration. Proc Inst Mech Eng Part J J Eng Tribol 229(4):362–375

Yue H, Deng J, Ge D, Li X, Zhang Y (2019) Effect of surface texturing on tribological performance of sliding guideway under boundary lubrication. J Manuf Process 47:172–182

Grabon W, Koszela W, Pawlus P, Ochwat S (2013) Improving tribological behaviour of piston ring–cylinder liner frictional pair by liner surface texturing. Tribol Int 61:102–108

Hamilton DB, Walowit JA, Allen CM (1966) A theory of lubrication by microirregularities. J Basic Eng 88(1):177–185

Tillmann W, Stangier D, Lopes-Dias N-F, Biermann D, Krebs E (2017) Adjustment of friction by duplex-treated, bionic structures for Sheet-Bulk Metal Forming. Tribol Int 111:9–17

Xu J, Feng P, Feng F, Zha H, Liang G (2021) Subsurface damage and burr improvements of aramid fiber reinforced plastics by using longitudinal–torsional ultrasonic vibration milling. J Mater Process Technol 297

Download references

This work is supported by grant 51875005 from the National Natural Science Foundation of China.

Author information

Authors and affiliations.

Mechanical Industry Key Laboratory of Heavy Machine Tool Digital Design and Testing, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing, 100124, China

Zhiwen Jiang, Dongju Chen, Kun Sun, Ri Pan & Jinwei Fan

Beijing Key Laboratory of Advanced Manufacturing Technology, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing, 100124, China

Beijing Institute of Control Engineering, Beijing, 100190, China

Yuhang Tang

You can also search for this author in PubMed   Google Scholar

Contributions

Zhiwen Jiang involved in conceptualization, methodology, and writing original draft. Dongju Chen supervised and provided fund support. Kun Sun, Ri Pan, Jinwei Fan, and Yuhang Tang conducted review, editing, and supervision.

Corresponding author

Correspondence to Dongju Chen .

Ethics declarations

Competing interests.

The authors declare no competing interests.

Additional information

Publisher’s note.

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Jiang, Z., Chen, D., Sun, K. et al. A systematic review of micro-texture formation based on milling: from mechanism, existing techniques, characterization to typical applications. Int J Adv Manuf Technol (2024). https://doi.org/10.1007/s00170-024-14177-4

Download citation

Received : 13 December 2023

Accepted : 21 July 2024

Published : 27 August 2024

DOI : https://doi.org/10.1007/s00170-024-14177-4

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

• Milling-based micro-texturing
• Surface texture generation mechanism
• Performance characterization
• Typical applications
• Find a journal
• Publish with us
• Track your research

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings

Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now .

• Advanced Search
• Journal List
• v.14(8); 2024
• PMC11340706

Determinants of clinical nurses’ patient safety competence: a systematic review protocol

Jong-hyuk park.

1 Seoul National University College of Nursing, Seoul, Republic of Korea

2 Research Institute of Nursing Science, Seoul National University, Seoul, Republic of Korea

Hanseulgi Lee

Gihwan park, associated data, introduction.

Patient safety has become a fundamental element of healthcare quality. However, despite the ongoing efforts of various organisations, patient safety issues remain a problem in the healthcare system. Given the crucial role of nurses in the healthcare process, improving patient safety competence among clinical nurses is important. In order to promote patient safety competence, it is essential to identify and strengthen the relevant factors. This protocol is for a systematic review aiming to examine and categorise the factors influencing patient safety competence among clinical nurses.

Methods and analysis

This review protocol is based on the Joanna Briggs Institute (JBI) Methodology for Systematic Reviews of Effectiveness and Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols. Four electronic databases, including Ovid-MEDLINE, CINAHL, Cochrane Library and EMBASE, will be used for the systematic review. After consulting with a medical librarian, we designed our search terms to include subject heading terms and related terms in the titles and abstracts. Databases from January 2012 to August 2023 will be searched.

Two reviewers will independently conduct the search and extract data including the author(s), country, study design, sample size, clinical setting, clinical experience, tool used to measure patient safety competence and factors affecting patient safety competence. The quality of the included studies will be assessed using the JBI critical appraisal tool. Because heterogeneity of the results is anticipated, the data will be narratively synthesised and divided into two categories: individual and organisational factors.

Ethics and dissemination

Ethical review is not relevant to this study. The findings will be presented at professional conferences and published in peer-reviewed journals.

PROSPERO registration number

CRD42023422486.

STRENGTHS AND LIMITATIONS OF THIS STUDY

• The review protocol has been rigorously and systematically developed according to the Joanna Briggs Institute Methodology for Systematic Reviews of Effectiveness and Preferred Reporting Items for Systematic Review and Meta-Analysis Protocol.
• This study will rigorously select relevant articles according to the Canadian Patient Safety Institute’s patient safety competence framework.
• The anticipated heterogeneity of contributing factors is expected to make it challenging to conduct a meta-analysis.
• This study will only include articles in English and exclude grey literature, which could result in potential publication bias.

Patient safety has become a global public health issue and a fundamental element of healthcare quality. 1 2 According to the WHO, patient safety is a framework of organised activities that creates cultures, processes, procedures, behaviours, technologies and environments in healthcare that consistently and sustainably lower risks, reduce the occurrence of avoidable harm, make errors less likely and reduce the impact of harm when it does occur. 3

Despite its importance, patient safety issues continue to undermine the healthcare system. 4 5 Annually, an estimated 421 million patients worldwide are admitted to hospitals while approximately 42.7 million patient safety incidents occur within the healthcare system. 6 The impact of patient safety incidents during patient care is noteworthy on a global scale, leading to over 3 million deaths annually. 7 An estimated 237.3 million medication errors occur annually in England, 8 resulting in a financial burden of more than 750 million pounds. 9 Approximately 15% of healthcare expenditures are allocated to address the consequences of patient safety incidents. 6 This results in a considerable decrease in the global economy costing trillions of dollars annually. 6 7 However, it has been found that a significant portion (ranging from 25% to 50% or more) of these events are preventable within the healthcare system. 6 10 11

In all dimensions of the healthcare process, nurses are responsible for patient safety. 12 Nurses, who spend more time with patients than other healthcare professionals, play a vital role in identifying patient safety risks and ensuring high-quality care. 12 , 14 Through careful monitoring of patient conditions, quick identification of risks, and supervision of the healthcare process, they actively contribute to patient safety. 13 15 In addition, nursing activities such as medication administration, infection control and fall prevention have a direct impact on patient safety. 16 Therefore, maintaining high levels of patient safety competence among nurses is crucial for decreasing patient safety issues and enhancing the quality of patient care. 13 17

The Quality and Safety Education for Nurses project identified the fundamental elements of quality and safety competence in nursing, including patient-centred care, teamwork and collaboration, evidence-based practice, quality improvement, safety and informatics. 18 These core principles improve evidence-based standards with a systemic perspective and enhance the quality of patient care. 19 In addition, the Canadian Patient Safety Institute (CPSI) outlines crucial aspects of patient safety competence, including the ability to recognise, respond to and disclose patient safety incidents, foster patient safety culture, promote effective teamwork and communication, ensure safety and manage risks, promote quality improvement and optimise both human and system factors. 20

The definition of patient safety competence encompasses the attitude, skills and knowledge that prevent unnecessary risk and harm to patients. 18 21 This competence helps prevent patient safety incidents and addresses latent problematic issues in the healthcare system. 13 22 A recent study revealed that patient safety competence can reduce preventable adverse events, including medication errors, surgical site infections, urinary tract infections and ventilator-associated pneumonia. 13

In addition to recognising the significance of the patient safety competence of nurses, there are many aspects of patient safety competence that require further investigation and understanding. 23 First, it is important to identify the factors relevant to patient safety competence and enforce the contributing factors. A study by Huh and Shin revealed that demographic factors such as age, education level, patient safety education and experience in patient safety activities are associated with patient safety competence. 16 However, prior studies have focused primarily on the individual attributes of patient safety competence and have not emphasised the organisational factors. 24 Patient safety is a complex process within the context of a system that requires collaborative efforts from both the individual and the organisation. 14 25

Although there are limited reviews of patient safety competence instruments, 26 27 there are currently no systematic reviews of the factors that contribute to the patient safety competence of clinical nurses. A previous review by Okuyama et al 26 conducted in 2011 explored patient safety competence across diverse healthcare professionals. However, the patient safety competence of clinical nurses may differ from other healthcare professionals. In addition, the most recent instruments of patient safety competence may not have been included in that review. Mortensen et al 27 published a scoping review of the instruments of patient safety competence in nursing. However, scoping reviews have methodological limitations that offer a general overview rather than a comprehensive in-depth analysis and they do not include a formal quality appraisal process. 28 Moreover, there is a lack of consensus on the definition of patient safety competence and its conceptual framework in that study.

This protocol aims to provide guidance for a systematic review to identify the factors affecting the patient safety competence of clinical nurses. To foster a comprehensive understanding of patient safety competence, we will categorise those factors into two domains: individual and organisational. Moreover, this study will encompass research that has examined the core concept of patient safety competence based on the CPSI framework. This review would essentially provide a starting point for identifying the determinants of patient safety competence.

Study objectives

The purpose of this research is to examine the factors that influence the patient safety competence of clinical nurses. The specific research questions include (1) what is the definition of patient safety competence, (2) what instruments for assessing patient safety competence are examined in this research and (3) what factors affect the patient safety competence of clinical nurses?

Before conducting this review, we thoroughly searched the International Prospective Register of Systematic Reviews, which revealed no ongoing systematic reviews of the factors influencing the patient safety competence of clinical nurses. To conduct a systematically organised review, this protocol was developed based on the Joanna Briggs Institute (JBI) Methodology for Systematic Reviews of Effectiveness. The JBI checklist, an organised tool to promote and support evidence-based practice, provides a rigorous systematic review process. 29 Some elements were updated and modified from the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocol. 30 We registered this systematic review with the International Prospective Register of Systematic Reviews (CRD42023422486). The systematic review started in August 2023 and included a preliminary search and pilot study selection process to screen the search results based on the eligibility criteria.

Search strategy (PICO) and data sources

This systematic review will explore the determinants of patient safety competence among clinical nurses (P-population). The study will examine the impact of various factors that either enhance or impair patient safety competence (I-indicator), comparing their effects on nurses exposed to these factors to those who are not exposed (C-comparison). The primary outcome to be measured will be the level of patient safety competence (O-outcome). According to the PICO statement guidelines, the search strategy was developed in consultation with a health sciences librarian. Four databases, including EMBASE, CINAHL, Ovid-Medline and Cochrane Library, will be explored from January 2012 to August 2023 ( online supplemental appendix A ). The reason for selecting this period is that the Medical Subject Headings for patient safety was introduced in 2012. The specific search strategy is presented ( table 1 ). In order to conduct a more thorough examination, we will use both backward and forward citation search methods.

This review will include studies involving clinical nurses directly engaged in providing patient care in hospitals. According to a previous study, clinical nurses consist of registered nurses or licensed practical/vocational nurses providing direct care to their patients in hospitals. 31 Therefore, this study aims to encompass a diverse group of clinical nurses, including medical, surgical and intensive care unit nurses. To minimise variations in competence attributed to distinct professional roles, articles exclusively focused on nurses not directly participating in independent front-line patient care, such as nursing students and nurse managers, will be excluded.

This study will explore multiple influencing factors that serve as indicators of patient safety competence. The JBI quality appraisal tools employ a rigorous assessment process to evaluate the validity and reliability of indicators. A diverse and heterogeneous range of tools is expected to be employed in the study.

This systematic review will allow for comparisons based on exposure to the indicators. Comparisons can be made between clinical nurses who have been exposed to specific factors and those who have not. Furthermore, the study enables comparisons across different hospital settings providing valuable insights into the variations in patient safety competence.

The primary outcome will be patient safety competence, which encompasses complex patient safety principles, including the CPSI’s patient safety competence. This competence includes the ability to recognise, respond to and disclose patient safety incidents; manage safety, risks and quality improvement; communicate effectively; foster teamwork; understand patient safety culture and optimise human and system factors. 20 The outcome measure will be rigorously evaluated for its validity and reliability.

Study design

The study will encompass original descriptive cross-sectional analyses, comparative research and mixed-method research. Only peer-reviewed articles on patient safety competence will be included, to ensure high-quality and reliable information. Grey literature will be excluded as it does not meet our criteria for being valid, rigorous and peer-reviewed.

Inclusion and exclusion criteria

All published studies examining factors related to the patient safety competence of clinical nurses directly involved in patient care in the hospital setting will be included. The measurement of patient safety competence among clinical nurses serves as the primary outcome in the included studies. According to the CPSI, 20 the competence should cover various attributes, including (1) patient safety culture; (2) teamwork; (3) communication; (4) safety, risk and quality improvement; (5) optimised human and system factors and (6) recognition, response and disclosure of patient safety incidents. The selected articles will be peer-reviewed, written in English and published from January 2012 to August 2023.

Articles exclusively focusing on nurses who are not directly engaged in front-line patient care, such as nurse managers, will be excluded. The review will not include studies in which the participants are individuals without official nursing licences, including nursing students and patients’ family members. Research exploring patient safety competence in populations other than nurses (eg, hospitalists and medical students) will also be excluded. Studies that focus exclusively on a single attribute, such as communication or medication competence, will be excluded. Additionally, to maintain methodological clarity with measurable indicators, qualitative studies will be excluded. Furthermore, review articles, theses and dissertations, conference abstracts, editorials, opinion articles and case studies will be excluded. Articles not available in full text will also be excluded.

Study selection

Using the Covidence platform, two independent reviewers will conduct the article screening process by evaluating the titles and abstracts and classifying them into the categories of relevant and irrelevant. Disagreements regarding irrelevant articles will be resolved through discussion between the two reviewers. Only articles classified as relevant during the initial screening will be selected for the subsequent step of full-text screening, which will also be conducted by the same two reviewers. During this stage, the reviewers will each compile their own list of relevant articles, which will then be compared. Any discrepancies will be resolved through discussion. For any unresolved discrepancies, a third reviewer will be consulted, and the final decision will be made by the entire team.

Data extraction

Two researchers will collect information independently based on the following criteria: the author(s), country, study design, sample size, clinical setting, clinical experience, instrument to measure patient safety competence and factors affecting patient safety competence. Any discrepancies between the results obtained by the two researchers will be resolved through discussion or with the involvement of a third reviewer.

Quality assessment

The JBI critical appraisal checklist will be used for a strict quality appraisal process. 32 The objective of the appraisal is to assess a study’s methodological quality and identify any potential bias in its design, conduct and analysis. 29 Two reviewers will independently evaluate the quality of every study included in the analysis. Any discrepancies between the reviewers regarding the risk of bias will be resolved through discussion, with the inclusion of a third reviewer when required. The results of the critical evaluation will be reported through narrative descriptions and a table. The outcomes of the quality appraisal will play a pivotal role in assessing the overall quality and reliability of the included studies. Since this review will encompass peer-reviewed articles, no study will be excluded solely based on its quality rating.

Data synthesis

Due to the expected diversity in research methods and outcome measures, the researchers will employ a narrative synthesis to incorporate the study findings, rather than conduct a meta-analysis. Recognising that individual and organisational factors are associated with patient safety competence, content analysis will be used to categorise the factors influencing clinical nurses’ patient safety competence into two groups: individual and organisational factors. Previous studies on nurses’ competence have examined both individual and organisational factors. 33 34

Patient and public involvement

This study will not include any patient involvement.

Ethical approval was not required for this review as it does not involve the collection of primary population data. The results will be presented at professional conferences and peer-reviewed open-access journals.

supplementary material

Online supplemental file 1.

Funding: The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

Prepublication history and additional supplemental material for this paper are available online. To view these files, please visit the journal online ( https://doi.org/10.1136/bmjopen-2023-080038 ).

Provenance and peer review: Not commissioned; externally peer reviewed.

Patient consent for publication: Not applicable.

• BMJ Open. 2024; 14(8): e080038.

Review Process File