structured literature review protocol

Structured literature reviews – A guide for students

This is a step-by-step guide aimed at Master's students undertaking a structured literature review as part of their Master's thesis.

There are several different kinds of literature reviews, but any literature review typically includes an extensive literature search. Whenever a systematic approach is used, the literature search features a methodical step-by-step procedure. However, as a Master's student, it might not be possible to fulfill all the criteria of a systematic review when writing a literature review-based thesis; you should rather do a structured literature review, which will include only certain aspects of the systematic review methodology.

In this guide we will go through the different steps of a structured literature review and provide tips on how to make your search strategy more structured and extensive. Additionally, make sure to follow any programme and course specific requirements.

Step 1: Formulate and delimit your research question

• It will be much easier for you to perform a structured information search if you first define and delimit your research question in a clear way.
• One way to define and structure your question is to break it down into different parts .
• PICO and PEO are two different frameworks that can be used for breaking down a research question into different parts.
• You also need to define the most important key concepts of your research question.

The formulation of your research question is partly connected to what kind of literature review you are doing. This article by Maria J. Grant and Andrew Booth usefully compares different kinds of reviews . While a systematic literature review is usually grounded in a clearly delimited and structured question, a scoping review may, for instance, feature a wider problem formulation. The wider a research question is, the larger number of search hits it tends to generate.

To be able to perform a literature review, you need to consider a subject area in which there seems to be a sufficiently large number of original research studies. Therefore, it may be a good idea to test search a database for previous research on the subject while you are trying to formulate and delimit your research question.

One way to structure your research question is to break it down into different parts. A well-delimited question often consists of three to four different parts. PICO and PEO are two examples of frameworks that can help you identify and define your research question.

• PICO ( P opulation, I ntervention, C omparison, O utcome) is primarily used for quantitative research questions.
• PEO ( P opulation, E xposure, O utcome) is primarily used for qualitative research questions.

Structuring your research question in accordance with a framework, such as PICO or PEO, will also help you decide on the inclusion and exclusion criteria of your literature review.

PICO & PEO

After you have delimited your research question, you also need to identify the key concepts that make up your question. Based on these key concepts, you will create " search blocks " that you will use to organise your search terms.

Step 2: Find search terms and create search blocks

• Test searching is a good way to investigate the terminology of a subject area and find search terms.
• Reading key articles can help you gather additional search terms for your final search strategy.
• Find subject headings  for PubMed with the help of the US National Library of Medicine's MeSH database.
• Find& free-text search terms by investigating what words that occur in the title and abstract of relevant articles.
• A good way of achieving a structured final search query is to arrange your search terms into search blocks ; these blocks should arise from the key concepts of your research question.

While working on a literature review-based thesis, you will need to search for articles on several occasions. In the beginning of your project, it is often good to do a couple of unstructured and simple search queries, so-called test searches, in academic databases. This way you are off to a good start, as test searching helps you investigate the terminology of your subject area and find relevant search terms. While the final search strategy is typically reported in full, you don't need to present your test queries in your thesis.

Try to find a couple of key articles, that is, articles that correspond to the type of studies that you are planning to include in your review. Use key articles to gather additional search terms for your final search strategy. Analyse the terminology of your key articles by examining what subject headings (MeSH terms, etc.) that the articles have been tagged with and what words that occur in the titles and abstracts.

Test search - find keywords and narrow down your topic

Test search in pubmed & cinahl.

To retrieve as many relevant studies as possible, you will need to include free-text search terms as well as subject headings in your final search strategy. Free-text search terms are words that occur in the article's title and abstract – words used by the authors themselves. Subject headings are subject-related words that an article is tagged with when the article is added to the database.

• In PubMed , articles are tagged with MeSH terms ( Me dical  S ubject  H eadings). You can look up and browse MeSH terms in the US National Library of Medicine's  MeSH database .
• Databases such as CINAHL , PsycInfo , ERIC , and Sociological Abstracts  have their own subject heading lists; look up subject headings in each database's subject heading list.
• There are also so-called free-text databases, such as Web of Science . These databases lack subject heading lists. Hence, when searching a free-text database, you can only use free-text search terms.

Find subject headings

An effective way to increase the structure of your final search strategy is to arrange your search terms in so-called  search blocks . Create your search blocks based on the key concepts of your research question.

Create search blocks

This search strategy worksheet might help you document and organise your search terms.

Download worksheet

• Worksheet for search terms (Word, 30.54 KB)

Step 3: Search in a structured way

• To get a comprehensive search result, you will need to search for articles in  several different databases .
• Your search strategy should be as uniform as possible in every database, but you may have to  adapt your use of subject headings .
• As you search the databases, combine your search terms and blocks with the help of  AND  and  OR .
• Save time by  documenting your search queries .

When doing a literature review-based thesis it is often wise to use at least two different databases. Many databases overlap, but may also contain unique content. At KI it is common for Master's students to use PubMed and Web of Science when doing a structured literature review as part of their Master's thesis. Depending on your research question, other databases may also be appropriate and useful. Read more about the most frequently used databases at KI .

Your search strategy should be as uniform as possible in every database. However, as mentioned in Step 2, databases may use different subject headings, and some databases only let you use free-text search terms. This means that you need to adapt your use of subject headings depending on the database.

Example: How subject headings may differ between databases 

If you want to search for articles about day surgery in PubMed, you should use the MeSH term Ambulatory Surgical Procedures . However, if you also want to perform your search in a database such as CINAHL, you need to use the corresponding CINAHL Headings term instead: Ambulatory Surgery .

There are many different ways of searching databases. Most databases have one simple, basic Google-like search box and one advanced search form. One advantage of the latter is that combining search terms with AND and OR is usually easier in an advanced search form, especially if you will be using both AND and OR within the same search query. However, you can often combine search terms with AND and OR in a basic search box too, and in that case, you often isolate your different search blocks from each other by enclosing each block in parentheses.

Example: A search query that contains AND, OR, and parentheses

( inflammatory bowel diseases OR ulcerative colitis OR crohn disease) AND (adolescent OR child OR young adult OR teenager) AND (self-management OR self care OR self efficacy )

By choosing the advanced search form you will also be able to exert more control over your search process. The advanced search form lets you specify more closely and decide exactly how you want the database to interpret your search terms; this way you can make your search query more precise.

You should always document your search strategy in order to remember what search terms you have used, how these search terms have been combined, and whether you have applied any limits to your search. The easiest way to do this is to copy and paste your search history from the database into a text document. Also, academic databases often let you create a personal account, so that you may save your searches online.

How to do a structured search in PubMed

Step 4: narrowing or broadening your search.

• Briefly examine your search results to see if you need to narrow or broaden your search query.
• Investigate whether your key articles are present in the search results.
• By using the advanced search form you can improve your search.

Prepare yourself for having to modify and redo your search query several times, before deciding on your final search strategy. After you have combined all your search terms and made your very first database search, you should examine the search results and analyse whether your search query is able to generate the type of search hits that you are looking for.

Analyse your search results

• Are all your key articles present in the search results, or are there some key articles that your search query is unable to retrieve?
• Are you getting too few search hits ? Investigate why. Perhaps you need to remove one of your search blocks, add one or several synonyms within a search block, or search for parts of words by truncating one or several of your free-text search terms, in order to broaden your search ?
• Does your search strategy generate too many non-relevant search hits that have nothing to do with your research question? Investigate why. Perhaps you need to add another search block, remove one of the synonyms from one of your search blocks, or search for phrases by enclosing one or several of your free-text terms in quotation marks, in order to narrow your search ?
• More tips on how to improve your search strategy .

It is important to remember that there is nothing wrong, per se, if your search query generates irrelevant hits. This is quite normal when performing a structured literature search. What's important is that your search strategy is able to retrieve the type of articles that you are looking for, and that you are not overwhelmed by the total number of hits (given the time frame of your thesis project).

We recommend that you use the advanced search form when improving your search strategy. By using the advanced search form, you will for example be able to specify which search fields your search terms must be present in.

Narrowing your search 

Broaden your search, how to specify the field you would like to search in pubmed, step 5: select and review articles.

• After you have completed your search, you will need to go through all your search hits and select which articles to include in your review.
• When selecting articles, read through the titles and abstracts of each article to decide its relevancy .
• Check the quality of each study that you include in your review.
• When checking the quality of articles, it is common to use critical appraisal worksheets or checklists .

Selecting articles

When you have completed and feel satisfied with your search, it is time to go through all the search hits and select which studies to include in your review. All relevant studies, that is, those studies that correspond to your research question and your previously set inclusion criteria, should be included. You decide on the relevancy of a study primarily by reading through the title and abstract. If you feel unsure, go through the whole article. You can describe your selection process with the help of a flow chart, such as the frequently used PRISMA flow diagram .

One of the challenges of systematic literature searches is that the search strategy should be exhaustive, but at the same time the number of search hits also needs to be kept within reasonable boundaries. A search query needs to be broad enough to retrieve all relevant studies, but on the other hand, this also means that a large portion of the search results will be irrelevant. Hence, even though your search strategy may have generated hundreds of hits, it is fine to only include ten to twenty articles in your review in the end.

Saving articles

If you create a personal account in a database it will be easier for you to save any references that you may find there. Another way of saving and organising article references is to use reference management software. There are several different reference management software, for example Endnote Online and Zotero.

Read more about reference management and see software guides.

Reviewing articles

When you have made your selection, you should critically examine the quality of all articles included in your review. The assessment is typically performed with the help of a critical appraisal guide or checklist. The purpose is to assess the reliability of the study results and whether there are any methodological flaws that may have impacted the results. Qualitative research articles are often reviewed with a focus on authenticity, credibility, and validity.

There are many different critical appraisal worksheets and checklists. Some examples are the SBU checklists for assessing the quality of randomized studies, observational studies, and qualitative research. In the course book How to do a systematic review in nursing there is a review guide that can be used for assessing different kinds of studies (both qualitative and quantitative); the original source is Caldwell, Henshaw & Taylor, 2011 .

Review worksheets and checklists contain criteria and questions that may help you identify flaws, errors, or bias. Sometimes different aspects of the study are scored separately. Later, all scores make up a final score that indicates whether the study is of high, medium, or low quality.

Many programmes and courses provide instructions on which checklists to use when reviewing articles, so check your course guidelines.

Step 6: Report your search strategy

• Describe your search strategy in a manner that makes it possible for your readers to replicate the search and get the same results.
• The search strategy is often presented in the form of a table .
• Look at the search history to see what words and limits that you have used when searching a database.

An important aspect of doing a structured literature review is transparency. It has to be easy for your readers to follow what you did when you searched and selected the articles that you have included in your review. In the method section of your literature review you should describe how you searched different databases. This is also where you describe any manual searches that you did. Search strategies are commonly reported in the form of tables. Present one table for each database.

You can examine your search terms and any limits you have applied when searching a database by visiting its search history.

Read more about how to report your search strategy and view examples.

Checklist for search strategies

Here is a checklist to help you review your own or someone else's search strategy.

If you would like us to get back to you, please submit your contact information in the form below along with your feeback.

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Systematic reviews.

• Should I do a systematic review?
• Writing the Protocol
• Building a Systematic Search
• Where to Search
• Managing Project Data
• How can a DML librarian help?

How do I write a protocol?

The protocol serves as a roadmap for your review and specifies the objectives, methods, and outcomes of primary interest of the systematic review. Having a protocol promotes transparency and can be helpful for project management. Some journals require you to submit your protocol along with your manuscript. 

A good way to familiarize yourself with research protocols is to take a look at those registered on PROSPERO. PROSPERO's registration form includes 22 mandatory fields and 18 optional fields which will help you to explain every aspect of your research plan. 

• PROSPERO - International prospective register of systematic reviews

A protocol ideally includes the following:

• Databases to be searched and additional sources (particularly for grey literature)
• Keywords to be used in the search strategy
• Limits applied to the search
• Screening process
• Data to be extracted
• Summary of data to be reported

Once you have written your protocol, it is advisable to register it. Registering your protocol is a good way to announce that you are working on a review, so that others do not start working on it.

The University of Warwick's protocol template is available below and is a great tool for planning your protocol. 

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• Step 2: Develop a Protocol

Systematic Reviews: Step 2: Develop a Protocol

Created by health science librarians.

• Step 1: Complete Pre-Review Tasks

Do I need to write a protocol?

Writing a protocol, make your protocol visible.

• Protocol FAQs
• 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

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About Step 2: Develop a Protocol

In Step 2, you will write your systematic review protocol. This is a detailed work plan for your systematic review. You will:

• Define the criteria you will use to screen literature.
• Decide where and how you will search for literature.
• Choose quality assessment tools to evaluate the literature.
• Decide how you will extract data from the articles you include.
• Upload your protocol to a website or registry to make it available to the public.

This page has checklists and templates to help you write your protocol. Librarians can help you refine your protocol based on systematic review best-practices.

Click an item below to see how it applies to Step 2: Develop a Protocol.

Reporting your review with PRISMA

For PRISMA, there are specific items you will want to report in your protocol.  For this step, review the PRISMA-P standards and the explanation document.

• PRISMA-P for Protocols
• PRISMA-P Explanation & Elaboration document
• PRISMA-P Checklist

Managing your review with Covidence

Covidence is a tool that can be used for screening, quality assessment, and data extraction. Decisions made in this stage will inform the logistics and completion of future review steps. Specify the use of Covidence in the protocol, if applicable, and note team member roles for these tasks.

How a librarian can help with Step 2

When writing your protocol, a librarian can help you :

• Develop and refine your research plan according to systematic review best practices 
• Advise on your literature searching methods documentation 
• Determine if/where to publish or share your completed protocol

What is a protocol? 

A protocol is a detailed work plan that describes how and why you are doing a systematic review. It includes your rationale and objectives, how you will search for literature, and how you will screen and synthesize what you find. It is best practice to develop a protocol and make it publicly available before starting a systematic review. 

Why should you write a protocol?

Your protocol will help your team navigate the systematic review process. It will also show readers how your completed systematic review might be different from your plan. This can help them understand whether there is any bias in your review results and conclusions. 

Uploading your protocol

You can upload a review protocol to a website or registry and make it accessible so researchers can know what reviews are planned or in process. While not an inclusive list, several options of places to upload or deposit your protocol can be found in our Protocol FAQ .  

Writing a Review Protocol: Good Practice and Common Errors

                            HSL Protocol Template                     

What to Include

Many  elements of a systematic review will need to be detailed in advance in the protocol. An example of items included in the protocol are:

• Team members
• Rationale and objectives of the review
• Eligibility criteria (also referred to as inclusion and exclusion criteria)
• Databases and key terms of the literature search (ideally, a full search strategy for at least one database)
• Process and tools for study selection (screening) , quality assessment , and data extraction
• Data items that will be extracted
• Methods of data synthesis

Use PRISMA to write your protocol

PRISMA is a set of standards about what to include in your systematic review. PRISMA 2015 has a special extension specifically for the best protocol reporting methods. The documents linked below (PRISMA-P Statement, E&E, and PRISMA-P Checklist) provide detailed instructions about how to write a good protocol.

• PRISMA-P 2015 Statement PRISMA reporting guideline for systematic review protocols.
• PRISMA-P 2015 E&E PRISMA-P Elaboration & Explanation document of the 2015 Statement (includes examples).
• PRISMA-P 2015 Checklist Choose between PDF and Word versions of the PRISMA-P 2015 Checklist
• UNC HSL Systematic Review Protocol Template Word document protocol template for systematic review protocols adapted from the PRISMA-P checklist
• Review Protocol Template by Sarah Vistintini A downloadable Word document that can be used to draft a systematic review protocol
• Evidence Synthesis Protocol Template A downloadable Word document that can be used to create a systematic review protocol
• PROSPERO Protocol Registration Form A PDF of the PROSPERO registration form
• Open Science Framework (OSF) Systematic Review Protocol Open Science Framework's (OSF) protocol template for preregistering systematic reviews, scoping reviews, and meta-analyses

You can upload your protocol to a website or registry and make it available to others. There are several places to upload or deposit your protocol listed below.  Alternatively, some journals publish systematic review protocols. If you plan to publish your protocol in a journal, make sure to check the protocol requirements on the journal website before submitting.

Compare protocol registries to see which tool might meet your needs.

• PROSPERO International prospective register of systematic reviews. Free.
• Open Science Framework (OSF) Open repository for scientific research. Free.
• Carolina Digital Repository Long-term storage and access for scholarly works, datasets, research materials and records produced by the UNC-CH community (free). Choose "Other Deposits" and then select "Poster, Presentation, Protocol, or Paper".
• Research Registry Register all types of research studies, from ‘first in man’ case reports to observational/interventional studies to systematic reviews and meta-analyses. Not free.
• INPLASY- The International Platform of Registered Systematic Review and Meta-analysis Protocols An international database created to help researchers around the world to register their systematic review protocols. Not free.
• Protocols.io A secure platform for developing and sharing reproducible methods. Create a protocol, collaborate with your team, then run as a checklist. Free.
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• 1. Assemble Your Team
• 2. Develop a Research Question
• 3. Write and Register a Protocol
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• 5. Screen Results
• 6. Assess for Quality and Bias
• 7. Extract the Data
• 8. Write the Review
• Additional Resources
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The Whats and Whys of Protocols

Systematic reviews and scoping reviews should have a protocol which helps to plan and outline the study methodology. The protocol should include:

• the rationale for the review
• key questions broken into PICO (or other structured research question) components
• inclusion/exclusion criteria
• literature searches for published/unpublished literature
• data abstraction/data management
• assessment of methodological quality/risk of bias of individual studies (not required for scoping reviews)
• data synthesis
• grading the evidence for each key question

Why should complete a protocol?

• A protocol is your planning document and roadmap for the project. It allows you to complete a systematic review efficiently and accurately, ensures greater understanding among team members, and makes writing the manuscript far easier.
• Many journals now require submitted systematic reviews to have registered protocols.
• The PRISMA Reporting Standard lists information about the systematic review protocol as an "essential element" (PRISMA 2020 Item 24)
• The Cochrane Handbook, The Institute of Medicine Standards, and others, all list completing a protocol as one of the important steps to a successful systematic review.
• Best practices in systematic reviews: the importance of protocols & registration
• Planning a systematic review? Think protocols

Writing a Protocol

Protocol templates:

• PRISMA for systematic review protocols (PRISMA-P) Checklist and explanation of what should be included in a systematic review protocol.
• The PROSPERO systematic review protocol template
• OSF Scoping Review Protocol Template and Guidance Document "The Guidance document is intended to be used in tandem with the Scoping Review Protocol Template. The Guidance document includes tips, examples, and details about each section of the protocol. The Template includes headings and subheadings to use to structure the protocol (e.g., which order to present the information, what level of detail, etc.).”
• JBI scoping review protocol template

Resources to help authors prepare a protocol for a systematic or scoping review:

• Institute of Medicine – Standards for Systematic Reviews - Section 2.6
• The Cochrane Handbook - Section ii.1.4
• JBI Manual for Evidence Synthesis - Section 1.3 (Systematic reviews) & 11.2 (Scoping reviews)

Where to Register a Protocol

After you write the protocol, you should register it with a review registry. There are numerous review registries available, such as PROSPERO or OSF. Registration is free and open to anyone undertaking systematic reviews. Some journals also publish systematic review protocols.

• PROSPERO A registry for systematic review protocols
• How to register with PROSPERO

OSF can be used to pre-register a systematic or scoping review protocol and to share documents such as a citation management library, search strategies, and data extraction forms. Unlike other registries, evidence synthesis author teams do not submit their protocols for review by an editorial board before they are accepted and pre-registered on OSF. Instead, create your own pre-registration.

• How to create an OSF registration
• OSF Registrations Form

Scoping reviews may not be registered with PROSPERO.  Currently, they can be registered with the Open Science Framework or Figshare.

Publishing a Protocol

• BioMed Central Protocols BioMed Central will consider protocols of any type of research for publication, following the standard peer review.
• BMJ Open BMJ Open "will consider publishing without peer review protocols that have formal ethical approval and funding from a recognized, open access advocating research-funding body". Otherwise, protocols are peer reviewed.
• JBI Evidence Synthesis Like systematic reviews, scoping review protocols can be published in some journals.
• Systematic Reviews, a BioMed Central journal This open access title publishes protocols of systematic reviews broadly related to health sciences.
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• Develop a Protocol

Evidence Synthesis, Systematic Review Services : Develop a Protocol

• Literature Review Types, Taxonomies
• Develop Your Research Question
• Select Databases
• Select Gray Literature Sources
• Write a Search Strategy
• Manage Your Search Process
• Register Your Protocol
• Citation Management
• Article Screening
• Risk of Bias Assessment
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• Browse Evidence Portals by Discipline
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• Additional Resources

Why Develop a Protocol?

As with any other research project, your research team should write a detailed protocol for how your systematic review will be conducted very early in the systematic review process. This will be a plan of action that your team will follow. 

 A protocol will describe the following general elements:

• Scope and rationale of the review
• How the team will execute and document the search for the research publications to be analyzed
• What inclusion/exclusion criteria will be used to screen and select the final research publications to be analyzed
• How the data collected will be analyzed

Systematic review reporting standards or reporting guidelines , such as PRISMA and ROSES, will detail the required elements your protocol document will need to make explicit, and later guide what will need to be included in any manuscripts reporting the results of the systematic review. Reporting standards/guidelines may differ across disciplines.

A reporting standard/guideline is developed by an organization and tells you WHAT you need to report on. The protocol is written by you and your team, and will specifically describe HOW those standards/guidelines will be met.

By creating a protocol, not only does the team have a plan of action, they also have minimized the risk for bringing subjectivity and inconsistency into the review process. Protocols should also be registered and published in a registry as a means to publicize the team’s intent to conduct the review. This is considered a best practice as it can reduce duplication of effort by other researchers intending to conduct a similar review project, and allow for peer-review of the project’s methodology.  Some journals may require that a systematic review manuscript submission have a registered protocol before considering the manuscript for publication.

Suggested places to register and publish a protocol are listed  here .

Protocol Examples

As you prepare to write your protocol, it may be helpful to review others.

Here are two protocols published in the journal  Environmental Evidence .

• Coates, J., Bostick, K.J., Jones, B.A. et al. What is the impact of aminoglycoside exposure on soil and plant root-associated microbiota? A systematic review protocol.  Environ Evid  11, 18 (2022). https://doi.org/10.1186/s13750-022-00274-y

Bekchanova, M., Campion, L., Bruns, S. et al. Biochar’s effect on the ecosystem services provided by sandy-textured and contaminated sandy soils: a systematic review protocol.  Environ Evid  10, 7 (2021). https://doi.org/10.1186/s13750-021-00223-1

Here are two protocols published in the journal  Campbell Systematic Reviews .

• Filges, T., Dietrichson, J. Viinholt, B.C.A., & Dalgaard, N.T. (2022). Service learning for improving academic success in students in grade K to 12: A systematic review.  Campbell Systematic Reviews , 18(1), e1210.  https://doi.org/10.1002/cl2.1210  
• Reith-Hall, E., & Montgomery, P. (2023). Communication skills training for improving the communicative abilities of student social workers.  Campbell Systematic Reviews , 19(1), e1309.  https://doi.org/10.1002/cl2.1309

Here is a protocol published in the PROCEED registry

• Bashira Chowdhury, Landon Hawk, Bradley Brazzeal, JoVonn Hill. What strategies do herbivores employ to exploit carnivorous plants?: a Systematic Map Protocol. PROCEED-23-00068 Available from:  https://www.proceedevidence.info/protocol/view-result?id=68 and  https://doi.org/10.57808/proceed.2023.3

Checklists of Reporting Standards by Discipline (forms, flow diagrams)

• ARRIVE Guidelines (Animal Research: Reporting of In Vivo Experiments) Checklist of information (ARRIVE Essential 10) to include in publications describing animal research. See also: Meridian (Menagerie of Reporting Guidelines Involving Animals): https://cvm.msu.edu/meridian
• PRISMA for Scoping Reviews (PRISMA-ScR) Checklist of 20 essential reporting items and 2 optional to include when completing a scoping review. (This review type serves to synthesize evidence and assess the scope of literature on a topic. It may also help determine whether a full systematic review of the literature is warranted.)
• PRISMA Statement (Preferred Reporting Items for Systematic Reviews, Scoping Reviews, and Meta-Analyses) Evidence-based minimum set of items for reporting in systematic reviews and meta-analyses. PRISMA primarily focuses on the reporting of reviews evaluating the effects of interventions, but can also be used as a basis for reporting systematic reviews with objectives other than evaluating interventions (e.g. evaluating aetiology, prevalence, diagnosis or prognosis).
• REFLECT Statement (Reporting Guidelines for Randomized Controlled Trials for Livestock and Food Safety) Evidence-based minimum set of items for trials reporting production, health, and food-safety outcomes.
• ROSES (Reporting standards for Systematic Evidence Syntheses including Systematic Map Protocols & Reports) Detailed forms for ensuring that evidence syntheses report their methods to the highest possible standards. The Collaboration for Environmental Evidence now requires that submitting authors of systematic review and map protocols complete the relevant ROSES checklist.
• STROBE-VET Statement (Strengthening the Reporting of Observational Studies in Epidemiology - Veterinary Extension) Reporting requirements for observational studies in veterinary medicine related to health, production, welfare, and food safety.

Inclusion and Exclusion Criteria

Inclusion and exclusion criteria set the boundaries for the review. They are determined after establishing the research question and ideally in advance of the comprehensive literature search. (It is important to note that exploratory or scoping searches should be performed in order to determine appropriate criteria). Some common variables used as inclusion and exclusion criteria are described below. Additionally, the popular mnemonics such as PICO/PECO, SPICE, and others you may use to help frame your research question  can also serve to guide the criteria you use to include or exclude research studies. 

Information about inclusion and exclusion criteria should be recorded as a paragraph or table within the methods section of the review. 

Common inclusion/exclusion criteria are:

• Date (or date range)
• Exposure of Interest (required experience or condition of participant or subject)
• Geographic location of study
• Language (of the study)
• Participants (by demographic)
• Peer review (or not--and may depend upon the research question to include, then, the gray literature)
• Reported outcomes
• Setting (specific location of research participants)
• Study Design
• Type of Publication (original research or other--akin to the peer-review condition, above)

Guide to Systematic Review Tools and Services, University of Melbourne Libraries https://unimelb.libguides.com/sysrev/inclusion-exclusion-criteria

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• Last Updated: Jun 27, 2024 11:27 AM
• URL: https://researchguides.library.wisc.edu/literature_review

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Cochrane Cochrane Interactive Learning

Cochrane interactive learning, module 2: writing the review protocol, about this module.

Part of the Cochrane Interactive Learning course on Conducting an Intervention Review, this module explains why a review protocol is a crucial step in planning and delivering a systematic review. This module teaches you about the components of a protocol, and how to define eligibility criteria using the PICO format.

45-60 minutes

What you can expect to learn (learning outcomes).

This module will teach you to:

• Recognize the importance of Cochrane Protocols
• Identify the eligibility criteria for studies to be included in a Cochrane Review
• Identify the information that should be included in the background of a Cochrane Review
• Recognize the key components of a well-written objective
• Recognize the structure of a protocol

Authors, contributors, and how to cite this module

Module 2 has been written and compiled by Dario Sambunjak, Miranda Cumpston and Chris Watts,  Cochrane Central Executive Team .

A full list of acknowledgements, including our expert advisors from across Cochrane, is available at the end of each module page.

This module should be cited as: Sambunjak D, Cumpston M, Watts C. Module 2: Writing the review protocol. In: Cochrane Interactive Learning: Conducting an intervention review. Cochrane, 2017. Available from https://training.cochrane.org/interactivelearning/module-2-writing-review-protocol .

Update and feedback

The module was last updated on September 2022.

We're pleased to hear your thoughts. If you have any questions, comments or feedback about the content of this module, please contact us .

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• Framework, Protocol, and Writing Steps

Reviewing Research: Literature Reviews, Scoping Reviews, Systematic Reviews: Framework, Protocol, and Writing Steps

• Differentiating the Three Review Types
• Working with Keywords/Subject Headings
• Citing Research

Using a framework to structure your question

Frameworks for research question:

• Frameworks for research questions in different disciplines (University of Maryland)

The process for developing a research question with concept map . (Central Michigan University Libraries)

This research guide offers a comprehensive explanation on the different framework models and provides examples . (James Cook University

What is a protocol

The protocol is the plan or methodology of your scoping or systematic review, it describes the rationale, hypothesis, and planned methods of the review. It should be prepared before a review is started and used as a guide to carry out the review. http://www.prisma-statement.org/Protocols/Default.aspx

The protocol should detail the criteria that the reviewers intend on using to include and exclude studies and to identify what data is relevant, and how the data will be extracted and mapped. It can be refined, as needed (report any changes).

• PRISMA for systematic review protocols (PRISMA-P) PRISMA-P was published in 2015 aiming to facilitate the development and reporting of systematic review protocols. Includes checklist.
• PRISMA ScR Extension Fillable Checklist The checklists can be downloaded for review authors to refer to when reporting scoping reviews to ensure they are in line with the PRISMA scoping reviews extension.
• PRISMA Flow Diagram The flow diagram depicts the flow of information through the different phases of a systematic review. It maps out the number of records identified, included and excluded, and the reasons for exclusions. Different templates are available depending on the type of review (new or updated) and sources used to identify studies.

Steps in Literature Review Process

Step 1: Define your research topic (define/refine scope )

Step 2: Identify the type of literature you will search (book chapters, articles, gray literature, case studies) criteria: dates, geographic region, methodology

Step 3: Search the literature, keep track of keywords, look at subject headings, track citations ( EndNote )

Step 4: Analyze and evaluate the collected literature: major themes, contrary themes, experts in the field, methodologies, popular theories, changes in perception or thoughts over time

Step 5: Categorize your citations: theme, chronological, theoretical, methodological

Step 5: Develop thesis statement or purpose statement

Step 6: Write paper

Step 7: Review your paper

• Learn how to write a review of literature (University of Wisconsin-Madison Writing Center)

Steps in Scoping Review Process

Step 1: Develop a protocol

Step 2: State your review question/objectives clearly

Step 3: Establish your criteria with rationale

Step 4: Search first database, scan references              search appropriate databases

Step 5: Search grey literature, if applicable

Step 6: Screen titles and a abstract by at least 2 reviewers

Step 7: Screen full text by at least 2 reviewers

Step 8: Charting form

Step 9: Chart data by at least 2 reviewers

Step 10: Present findings in diagrams or tables

• Current Best Practices for Conducting a Scoping Review (University of Toronto
• JBI Manual for Evidence Synthesis 11.1 Introduction to Scoping reviews 11.2 Development of a scoping review protocol 11.3 The scoping review and summary of the evidence

Arksey, & O’Malley, L. (2005). Scoping studies: towards a methodological framework . International Journal of Social Research Methodology, 8 (1), 19–32. https://doi.org/10.1080/1364557032000119616  UB Libraries online access The article distinguishes between different types of scoping studies and indicate where these stand in relation to full systematic reviews. It consider the advantages and limitations of the approach and suggest that a wider debate is called for about the role of the scoping study in relation to other types of literature reviews.

Steps in Systematic Review Process

Step 1: Frame the research question

Step 2: Develop the protocol

Step 3: Engage a librarian to help with a comprehensive search of the literature

Step 4: Assess the retrieved articles by scanning titles and abstracts based on criteria with at least 2 reviewers

Step 5: Assess and evaluate the results with at least 2 reviewers (full text)

Step 6: Manage and report data (PRISMA 2020)

Step 6: Extract data with at least 2 reviewers

Step 7: Analyze results 

Step 8: Interpret results

• Cochrane Training: Starting a Review

Khan, K. S., Kunz, R., Kleijnen, J., & Antes, G. (2003). Five steps to conducting a systematic review. Journal of the Royal Society of Medicine, 96(3), 118–121. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC539417/

• Systematic Reviews in the Health Sciences by Molly Maloney Last Updated Jun 11, 2024 739 views this year
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• Next: Working with Keywords/Subject Headings >>

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What is a systematic review?

A systematic review is a firmly structured literature review, undertaken according to a fixed plan, system or method. As such, it is highly focused on a particular and explicit topic area with strict research parameters. Systematic reviews will often have a detailed plan known as a protocol, which is a statement of the approach and methods to be used in the review prior to undertaking it. 

Systematic review methodology is explicit and precise because it aims to minimise bias, thereby enhancing the reliability of any conclusions. It is therefore considered an evidence-based approach. Systematic reviews are commonly used by health professionals, but also policy makers and researchers. 

There is information about the difference between a systematic review and a literature review on this page. If you are undertaking systematic approach to a literature review, however, you might find certain aspects of this guide useful. 

LITERATURE REVIEW VS SYSTEMATIC REVIEW

You can find further information on literature reviews on our  literature reviews page .

How we can help

What we need you to do: .

• Have a firm idea of your research question or area 
• List your main keywords and alternatives. You may want to use a table to organise your keywords. 
• Think about how you will use your keywords to search using connectors such as AND/OR 
• Define what you want to include and exclude from your search 
• Consider where you want to search 
• Run some initial searches and identify any problems or issues you want to discuss 

What your Librarian can help you with:  

• Identifying relevant databases and other subject resources that could be used to supplement your review 
• Demonstrating library resources for use in the review  
• Replicating searches on other databases and resources 
• Reviewing your search strategy/approach 
• Directing you to referencing software support 
• Suggesting ways to save and document your search results 
• Helping to locate difficult to find material, using the  Request It! service
• PREPARATION AND PLANNING
• review types
• SEARCH METHODS
• GREY LITERATURE
• DOCUMENTATION AND DATA MANAGEMENT
• FURTHER INFORMATION AND RESOURCES

A Guide to Evidence Synthesis: 0. Develop a Protocol

• Meet Our Team
• Our Published Reviews and Protocols
• What is Evidence Synthesis?
• Types of Evidence Synthesis
• Evidence Synthesis Across Disciplines
• Finding and Appraising Existing Systematic Reviews
• 0. Develop a Protocol
• 1. Draft your Research Question
• 2. Select Databases
• 3. Select Grey Literature Sources
• 4. Write a Search Strategy
• 5. Register a Protocol
• 6. Translate Search Strategies
• 7. Citation Management
• 8. Article Screening
• 9. Risk of Bias Assessment
• 10. Data Extraction
• 11. Synthesize, Map, or Describe the Results
• Evidence Synthesis Institute for Librarians
• Open Access Evidence Synthesis Resources

What is a protocol?

What is a protocol .

An evidence synthesis protocol states your rationale, hypothesis, and planned methodology.   Much like a blueprint for a house, a protocol outlines the planned framework for the evidence synthesis. Members of the team use the protocol as a guide to conduct the research. It is recommended that you register your protocol prior to conducting your review. This will improve transparency and reproducibility, reduce bias, and will also ensure that other research teams do not duplicate your efforts. A protocol template and checklist are included on this page, as well as a checklist for structured literature reviews that serves as a similar document to an  evidence synthesis  protocol.

• Evidence Synthesis Protocol Template Use this document as a template to prepare a protocol for a range of evidence synthesis methodologies (such as systematic reviews, scoping reviews, or systematic maps).
• Planning Worksheet for Structured Literature Reviews Writing a literature review for a research paper or as part of your thesis? Even if you’re not performing a full evidence synthesis, completing the items on this checklist and keeping them as record of your planned work (like a study protocol) ensures reproducibility, transparency, and reduction of bias.
• PRISMA Checklist Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) is an evidence-based minimum set of items for reporting in systematic reviews and meta-analyses. The 27 checklist items pertain to the content of a systematic review and meta-analysis, which include the title, abstract, methods, results, discussion and funding.
• PRISMA Extension for Scoping Reviews The PRISMA extension for scoping reviews, or PRISMA-ScR for short, contains 20 essential reporting items and 2 optional items to include when completing a scoping review.
• PRISMA Extension for Network Meta-Analysis The PRISMA extension for network meta-analysis, or PRISMA-NMA, provides guidance for reporting systematic reviews comparing multiple treatments using direct and indirect evidence in network meta-analyses. In addition to providing guidance It also highlights educational information related to key considerations in the practice of network meta-analysis.
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• Next: 1. Draft your Research Question >>
• Last Updated: Jun 14, 2024 1:30 PM
• URL: https://guides.library.cornell.edu/evidence-synthesis

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Systematic review protocols: an introduction

Affiliation.

• 1 Childrens Nursing, University of Herftordshire, Hatfield, UK.
• PMID: 19911652
• DOI: 10.7748/nr2009.10.17.1.34.c7337

Systematic reviews are a thorough and efficient method of appraising literature and providing an evidence base for practice. However, to ensure that they are undertaken in a structured and comprehensive manner, it is crucial that a systematic review protocol is first formulated. While resources such as the Cochrane Collaboration provide extensive and valuable information in relation to the issues that should be considered, there is little immediately available in the nursing literature.

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