This resource provides a simple definition and example of a literature review and explains where this kind of writing fits into academic work at various levels of study. For instruction on how to do it, see links at the end of this resource.
What is literature?
In an academic context, ‘literature’ means academic publications, not fiction. It refers to research articles in peer-reviewed journals, books, and various other kinds of publication relevant to a given topic. Using a good library’s search tools, you can quite quickly work out how much literature there is on any given topic. If you are asked to check ‘the literature’ to see what experts in a particular field know, debate, and still want to find out, it means the professional publications that represent the given area of knowledge and practice.
What is a review?
When you are asked to ‘review the literature' on a topic, you’re being asked to gather a lot of reading material, select the best, read it carefully, and write about how the selected publications deal with a particular issue or question. The aim is to give a good overview of what is known, who is developing the knowledge, and how their views concur or differ. Most often, the aim of a review is also to identify what is still not known or well understood and position new research into that field.
Depending on the level of study, and time available, a review might be a brief report on what the main experts are saying, or a lengthy critical discussion. So if you have to write one, check first how many words you’re expected to write, how many sources to read, and how much to critically 'discuss' them (as opposed to simply summarising and reporting what they say).
A simple review might be under 2,000 words on a small number of publications – just identifying key issues discussed by experts, or giving a 'state of the art' account of ideas and developments in an area of research. A more complex review would be part of a formal research proposal or a chapter of a PhD thesis, discussing scores of previous key studies, and explaining why further research needs to be done (identifying a gap in knowledge, and arguing the need to know more or understand better). Short summary reviews are used to give introductory context for research articles, while very comprehensive reviews are done as stand-alone publications, to give an overview of an entire knowledge domain, its problems and current approaches, based on a systematic investigation of hundreds of publications.
How does a literature review differ from an annotated bibliography?
| Literature Review | Annotated Bibliography | |
|---|---|---|
| Structure |
A literature review is written in the style of an essay, which consists of three parts: Introduction, Main Body, and Conclusion. Sources can be re-used as much as needed to support the writer's argument. |
An annotated bibliography is a list of sources accompanied by a short summary and/or evaluation. Each source is mentioned only once and they are organised alphabetically. |
| Purposes |
In general, a literature review will provide background information on a particular topic by summarising, comparing and contrasting existing knowledge, and acknowledging prominent researchers in that area. If you are writing the literature review to provide justification for your research project, then you will need to identify the gap in knowledge, indicate the need for further research/investigation, and clearly state the significance of your research. (See Biology Example below) If your literature review is not specifically attempting to justify a research project, then it is more likely to be a synthesis and evaluation of knowledge and practice in a particular area. (See Health Sciences example below) |
Provide readers with a short summary and critical appraisal of the sources cited |
Biology example
The following example is an excerpt from a Biology student’s literature review.
Although studies have shown that diet has an important influence on a mammal's overall biology (e.g. McNab 1983), little is known about the feeding ecology of many Australian species. One species, the yellow-bellied glider (Petaurus australis), which weighs up to approximately 700g, is the largest of the arthropod and exudate-feeding marsupial gliders (see Smith & Lee 1984). It has a widespread but patchy distribution in eastern Australia and is characterized by low population densities (Henry & Craig 1984; Kavanagh 1984). Relatively little research has been centred on the feeding behaviour of this species because of difficulty in its detection and capture (Craig & Belcher 1980).
One study (Wakefield, 1970) concluded that while yellow-bellied gliders obtain sap from the 'V'-shaped incisions they make in the trunks of various species of eucalypt, arthropods comprise the bulk of their diet. This conclusion, however, was based on limited feeding observations and the irregular occurrence of these 'sap-site' trees.
Other studies conducted analyses on faecal samples from north Queensland and Victoria respectively (Smith & Russell 1982; Henry & Craig 1984; Craig 1985) to determine feeding behaviour. These studies found the presence of arthropods, eucalypt sap, nectar and honeydew. However, as insect and plant exudates are almost tota1ly digested and leave little trace in the faeces, other indicators must be used to infer their use (Smith & Russell 1982). Bark, for example, is used as an indicator of eucalypt sap. Faecal analysis, therefore, does not allow a precise determination of the relative importance of each of the separate dietary items.
Qualitative observations of feeding behaviour in gliders have also been carried out (Henry and Craig 1984; Craig 1985; Kavanagh and Rohan-Jones 1982; Kavanagh 1987a,b). In these studies each observation is scored equal, regardless of duration, thus these data indicate only the presence or absence of food items in the diet, not their relative use.
A study employing the use of timed (i.e. quantitative) feeding observations is necessary to give a better resolution of the species' dietary requirements. This study was aimed at achieving this by addressing the following question: are different food resources exploited in different proportions throughout the year?
Literature review comments
- Introduces the subject of the study & identifies gap in previous research
- Although studies have shown [identifies gap in previous research] that diet has an important influence on a mammal's overall biology (e.g. McNab 1983),
- little is known [identifies gap in previous research] about the
- feeding ecology [introduces the subject of the study] of many Australian species. One species,
- the yellow-bellied glider (Petaurus australis) [introduces the subject of the study], which weighs up to approximately 700g, is the largest of the arthropod and exudate-feeding marsupial gliders (see Smith & Lee 1984). It has a widespread but patchy distribution in eastern Australia and is characterized by low population densities (Henry & Craig 1984; Kavanagh 1984).
- Relatively little research has been centred on the feeding behaviour of this species [identifies gap in previous research] because of difficulty in its detection and capture (Craig & Belcher 1980).
- Summarises the conclusions of the earliest relevant study and identifies limitations in method
- One study (Wakefield, 1970) concluded that while yellow-bellied gliders obtain sap from the 'V'-shaped incisions they make in the trunks of various species of eucalypt, arthropods comprise the bulk of their diet. [summarises the conclusions of the earliest relevant study]
- This conclusion, however, was based on limited feeding observations and the irregular occurrence of these 'sap-site' trees. [identifies limitations in method]
- Groups another set of studies according to method, summarises findings, and identifies limitations
- Other studies conducted analyses on faecal samples from north Queensland and Victoria respectively (Smith & Russell 1982; Henry & Craig 1984; Craig 1985) to determine feeding behaviour. [groups another set of studies according to method]
- These studies found the presence of arthropods, eucalypt sap, nectar and honeydew. [summarises findings]
- However, as insect and plant exudates are almost tota1ly digested and leave little trace in the faeces, other indicators must be used to infer their use (Smith & Russell 1982). Bark, for example, is used as an indicator of eucalypt sap. Faecal analysis, therefore, does not allow a precise determination of the relative importance of each of the separate dietary items. [identifies limitations]
- Qualitative observations of feeding behaviour in gliders have also been carried out (Henry and Craig 1984; Craig 1985; Kavanagh and Rohan-Jones 1982; Kavanagh 1987a,b). [groups another set of studies according to method]
- In these studies each observation is scored equal, regardless of duration, thus [summarises findings]
- these data indicate only the presence or absence of food items in the diet, not their relative use. [identifies limitations]
- Identifies gap - states aims of the research – shows how this research will fill the gap
- A study employing the use of timed (i.e. quantitative) feeding observations is necessary to give a better resolution of the species' dietary requirements. This study was aimed at achieving this by addressing the following question: are different food resources exploited in different proportions throughout the year? [Identifies gap - states aims of the research – shows how this research will fill the gap]
Health Sciences example
The following paragraph is an excerpt from a Health Sciences literature review.
Data from numerous studies reveal that unsafe food-handling is more common in some consumer groups than in others (Yang et al. 1998; Altekruse et al. 1999). Young adults and those with education beyond high school are more likely to be exposed to unsafe food handling than other groups (Altekruse et al. 1999; Patil et al. 2005; McArthur et al. 2007). A large-scale US meta-analysis of 20 food safety studies conducted by Patil et al. (2005) indicated that males, young adults, those without a high school education and those with high incomes reported the lowest level of knowledge about good hygiene and cross-contamination prevention practices. The literature further demonstrated that young adults both engage in unsafe food-handling practices (Unklesbay et al. 1998; Morrone and Rathbun 2003; Haapala and Probart 2004; McArthur et al. 2007), and report low levels of food safety knowledge. However, the research investigating safe food handling among this population is limited (Unklesbay et al. 1998; McArthur et al. 2007).
Literature review comments
- Introduces the topic of the paragraph with the major finding in the literature to be discussed
- Data from numerous studies reveal that unsafe food-handling is more common in some consumer groups than in others (Yang et al. 1998; Altekruse et al. 1999). Young adults and those with education beyond high school are more likely to be exposed to unsafe food handling than other groups (Altekruse et al. 1999; Patil et al. 2005; McArthur et al. 2007).
- Integrates and summarises the studies
- A large-scale US meta-analysis of 20 food safety studies conducted by Patil et al. (2005) indicated that males, young adults, those without a high school education and those with high incomes reported the lowest level of knowledge about good hygiene and cross-contamination prevention practices. The literature further demonstrated that young adults both engage in unsafe food-handling practices (Unklesbay et al. 1998; Morrone and Rathbun 2003; Haapala and Probart 2004; McArthur et al. 2007), and report low levels of food safety knowledge.
- Evaluation of the findings
- However, the research investigating safe food handling among this population is limited (Unklesbay et al. 1998; McArthur et al. 2007).
- However, the research investigating safe food handling among this population is limited (Unklesbay et al. 1998; McArthur et al. 2007).