sentence starters for a literature review

Academic Phrasebank

Referring to sources

• GENERAL LANGUAGE FUNCTIONS
• Being cautious
• Being critical
• Classifying and listing
• Compare and contrast
• Defining terms
• Describing trends
• Describing quantities
• Explaining causality
• Giving examples
• Signalling transition
• Writing about the past

One of the distinguishing features of academic writing is that it is informed by what is already known, what work has been done before, and/or what ideas and models have already been developed. Thus, in academic texts, writers frequently make reference to other studies and to the work of other authors. It is important that writers guide their readers through this literature. This section of  Academic Phrasebank  lists some of the phrases that writers may use for this purpose.

A note on the literature review: It is the purpose of the literature review section of a paper or dissertation to show the reader, in a systematic way, what is already known about the research topic as a whole, and to outline the key ideas and theories that help us to understand this. As well as being systematic, the review should be evaluative and critical of the studies or ideas which are relevant to the current work. For example, you may think a particular study did not investigate some important aspect of the area you are researching, that the author(s) failed to notice a weakness in their methods, or that their conclusion is not well-supported (refer to  Being Critical ).

A note on referencing style: The way a writer refers to other sources varies somewhat across different disciplines. In some cases, where the individual author is important, the author’s name will be the main subject of the sentence; in other cases, the author’s name may only be mentioned in brackets ( … ) or via a number notation system (e.g. footnotes and endnotes). The ‘author as subject’ style is less common in the empirical disciplines (sciences) and more commonly used in the humanities. Different referencing systems are used in different disciplines. In the majority of the examples given here, the Harvard in-text referencing system has been used.

A note on verb tenses: For general reference to the literature, the present perfect tense (have/has + verb participle) tends to be used. For reference to specific studies carried out in the past, the simple past tense is most commonly used. This is normally the case where a specific date or point in time in the past forms a part of the sentence. When referring to the words or ideas of writers, the present tense is often used if the ideas are still relevant, even if the author is no longer alive. The examples given below reflect these general patterns, but these are by no means rigid.

General comments on the relevant literature

The literature on X has highlighted several … Different theories exist in the literature regarding … More recent attention has focused on the provision of … There are relatively few historical studies in the area of … A large and growing body of literature has investigated … Much of the literature since the mid-1990s emphasises the … Much of the current literature on X pays particular attention to … There is a large volume of published studies describing the role of … The existing literature on X is extensive and focuses particularly on … There is a relatively small body of literature that is concerned with … The generalisability of much published research on this issue is problematic. A considerable amount of literature has been published on X. These studies … The academic literature on X has revealed the emergence of several contrasting themes. Previous research findings into X have been inconsistent and contradictory (Smith, 1996; …).

Previous research: a historical perspective

Research into X has a long history. For many years, this phenomenon was surprisingly neglected by … Only in the past ten years have studies of X directly addressed how … Prior to the work of Smith (1983), the role of X was largely unknown. Over the past decade, most research in X has emphasized the use of … In recent years, there has been an increasing amount of literature on … Early examples of research into X include … (Smith, 1962; Jones, 1974). During the past 30 years, much more information has become available on … The first serious discussions and analyses of X emerged during the 1970s with … Over the past two decades, major advances in molecular biology have allowed … Historically, research investigating the factors associated with X has focused on … It is only since the work of Smith (2001) that the study of X has gained momentum. The construct of X was first articulated by Smith (1977) and popularised in his book: … Around the early 1960s, small-scale research and case studies began to emerge linking … It was not until the late 1960s that historians considered X worthy of scholarly attention. Awareness of X is not recent, having possibly first been described in the 5th century BCE by …

Previous research: methodological approaches taken

Most research on X has been carried out in … Most researchers investigating X have utilised … Using this approach, researchers have been able to … Several systematic reviews of X have been undertaken. The vast majority of studies on X have been quantitative. What we know about X is largely based on observational studies. There are a number of large cross-sectional studies which suggest … Much of the previous research on X has been exploratory in nature. Much of the X research has focused on identifying and evaluating the … What we know about X is largely based upon empirical studies that investigate … Publications that concentrate on X more frequently adopt a historical or chronological approach …

Previous research: area investigated

To date, several studies have investigated … A number of studies have begun to examine … Various studies have assessed the efficacy of … Researchers attempted to evaluate the impact of … A great deal of previous research into X has focused on … Several studies have used longitudinal data to examine … Previous studies have explored the relationships between X and Y. Twenty cohort study analyses have examined the relationship between … A number of authors have considered the effects of … (Smith, 2003; Jones, 2004). At least 120 case-control studies worldwide have examined the relationship between … Numerous studies have attempted to explain … (for example, Smith, 1996; Jones, 1998; …).

Previous research: what has been established or proposed

Several lines of evidence suggest that … Previous research has established that … Data from several studies suggest that … Recent evidence suggests that … (Smith, 2020; …). It is now well established from a variety of studies that … New findings amongst X provides further evidence that …

A number of studies have postulated a convergence between … Recently, considerable evidence has accumulated to show that … Surveys such as that conducted by Smith (2015) have shown that … Many recent studies (e.g. Smith, 2019; Jones, 2020) have shown that … Traditionally, it has been argued that … (e.g. Smith, 1960; Jones, 1972). Several biographies of Brown have been published. Smith (2016) presents …

In previous studies on X, different variables have been found to be related to … Many historians have argued that … (e.g. Jones, 1997; Brown, 1999; Smith, 2019). There is a consensus among social scientists that … (e.g. Smith, 2019; Jones, 2020; … Data from several sources have identified the increased X and Y associated with obesity. Recently, in vitro studies have shown that X can … (Smith et al. , 2018; Jones et al. , 2021). It has been demonstrated that a high intake of X results in damage to … (Smith, 2015; …).

Stating what is currently known about the topic

X increases when … (Smith, 2015) X is able to affect Y (Smith, 2015; Jones, 2020). X is positively related to Y (Smith, 2015; Jones, 2020). X is proportional to Y as expressed by the… (Smith, 2015). X is one of the most important … (Smith, 2015; Jones, 2020). X is one of the most intense reactions following Y (Jones, 2020). A relationship exists between X and Y (Smith, 2015; Jones, 2020). X is a principal determining factor of Y (Smith, 2015; Jones, 2020). There is an unambiguous relationship between X and Y (Smith, 2015). X is significantly reduced during the first months of … (Smith, 2015; Jones, 2020). X has been found to oppose the anti-inflammatory actions of Y on Z (Smith, 2020).

Reference to a previous investigation: researcher prominent

Smith’s comparative study (2017) found that … Jones’s comprehensive review concluded that … Brown’s (1998) model of X assumes three main … Smith’s cross-country analysis (2017) showed that … Jones’s (2010) review of the literature concluded that … Brown’s (2022) recent analysis of X provides a strong critique of …

Reference to a previous investigation: time prominent

In 1959, a seminal article was published entitled … Following this period, Smith actively searched for X. In the 1950s, Smith pointed to some of the ways in which … Thirty years later, Smith (1974) reported three cases of X which … Almost 20 years ago, Jones (1995) formulated his X theory, centred around …

Reference to a previous investigation: investigation prominent

One longitudinal study found that … A seminal study in this area is the work of … One study by Smith (2014) examined the trend in … A recent study by Smith and Jones (2012) involved … A qualitative study by Smith (2003) described how … A recent systematic literature review concluded that … Preliminary work on X was undertaken by Jones (1992). A longitudinal study of X by Smith (2012) reports that … A key study comparing X and Y is that of Smith (2010), in which … The first systematic study of X was reported by Smith  et al.  in 1986. Detailed examination of X by Smith and Jones (1961) showed that … Analysis of the genes involved in X was first carried out by Smith  et al.  (1983). A significant analysis and discussion on the subject was presented by Smith (1988). The study of the structural behaviour of X was first carried out by Jones  et al.  (1986). A small scale study by Smith (2015) reached different conclusions, finding no increase in … The study by Jones (1990) offers probably the most comprehensive empirical analysis of …

Reference to a previous investigation: topic prominent

To determine the effects of X, Jones  et al . (2005) compared … X was originally isolated from Y in a soil sample from … (Jones  et al. , 1952). The electronic spectroscopy of X was first studied by Smith and Jones in 1970. X formed the central focus of a study by Smith (2002) in which the author found … To better understand the mechanisms of X and its effects, Jones (2013) analysed the … X was first demonstrated experimentally by Pavlov (Smith, 2002). In his seminal study … The acid-catalyzed condensation reaction between X and Y was first reported by Smith in 1872. The way in which X is regulated was studied extensively by Smith and colleagues (Smith  et al.  1995 and 1998).

Reference to what other writers do in their published work

In Chapter 2, Smith provides us with a number of important … In the subsequent chapter, Smith examines the extent to which … By drawing on the concept of X, Smith has been able to show that … Some analysts (e.g. Smith, 2015) have attempted to draw fine distinctions between … Drawing on an extensive range of sources, the authors set out the different ways in which … Other authors (see Smith, 2010; Jones, 2014) question the usefulness of such an approach.  

Reference to another writer's idea or position

As noted by Smith (2003) X is far more cost effective, and therefore … According to Smith (2003), preventative medicine is far more cost effective, and therefore … 

Synthesising material: supporting evidence or ideas

Similarly, Jones (2015) found that X … This is consistent with the data obtained by … Smith (1995) makes a similar point in his study of X … In the same vein, Smith (1995) in his book XYZ notes This view is supported by Jones (2015) who writes that Along the same lines, Smith (1995) subsequently argued that … Smith argues that her data support Jones’s (1995) view that Jones’s (1986) work on X is complemented by Smith’s (2009) study of Almost every paper that has been written on X includes a section relating to A broadly similar point has also recently been made by Johnson (2019), who …

Synthesising material: contrasting evidence or ideas

Other writers have argued that … Other studies have concluded that … Unlike Smith, Jones (2013) argues that In contrast to Smith, Jones (2013) argues that Smith (2010) presents an X account, whilst Jones (2011) While Smith (2008) focuses on X, Jones (2009) is more concerned with A broader perspective has been adopted by Smith (213) who argues that Contrary to previously published studies, Jones et al. demonstrated the efficacy of… This result conflicts with Smith’s (1965) previously mentioned study which found that … Conversely, Smith (2010) reported no significant difference in mortality between X and Y.

Some ways of introducing quotations

Commenting on X, Smith (2003) argues: ‘… …’ As Smith (2004: 215) states: ‘there are many good reasons to be sceptical’. As Smith argues: ‘In the past, the purpose of education was to …’ (Smith, 2000:150). In the final part of the  Theses on Feuerbach , Marx writes: ‘Philosophers have hitherto only …’ Smith concludes: ‘The idea of development stands today like a ruin in …’ (Smith, 1992: 156).

Summarising the review or parts of the review

Together, these studies indicate that … Overall, these studies highlight the need for … Considering all of this evidence, it seems that … Collectively, these studies outline a critical role for… In all the studies reviewed here, X is recognised as … The evidence presented in this section suggests that … The studies presented thus far provide evidence that … Taken together, these studies support the notion that … Overall, there seems to be some evidence to indicate that … Together these studies provide important insights into the … All of the studies reviewed here support the hypothesis that … Two important themes emerge from the studies discussed so far: However, such studies remain narrow in focus dealing only with … The evidence reviewed here seems to suggest a pertinent role for … These studies clearly indicate that there is a relationship between … In view of all that has been mentioned so far, one may suppose that … There remain several aspects of X about which relatively little is known.

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