Introduction to literature reviews
What is a literature review?
In essence, a literature review identifies, evaluates and synthesises the relevant literature within a particular field of research. It illuminates how knowledge has evolved within the field, highlighting what has already been done, what is generally accepted, what is emerging and what is the current state of thinking on the topic. In addition, within research-based texts such as a Doctoral thesis, a literature review identifies a research gap (i.e. unexplored or under-researched areas) and articulates how a particular research project addresses this gap.
What is meant by the term literature?
Literature refers to a collection of published information/materials on a particular area of research or topic, such as books and journal articles of academic value. However, your literature review does not need to be inclusive of every article and book that has been written on your topic because that will be too broad. Rather, it should include the key sources related to the main debates, trends and gaps in your research area.
What is meant by the term review?
To review the literature means to be able to identify:
- what has been established, discredited and accepted in your field*
- areas of controversy or conflict among different schools of thought
- problems or issues that remain unsolved
- emerging trends and new approaches
- how your research extends, builds upon, and departs from previous research.
A review of literature presents much more than a summary of relevant sources. The act of reviewing involves evaluating individual sources as well as synthesising these sources in order to gain a broad view of the field. At this ‘field level’, a literature review discusses common and emerging approaches, notable patterns and trends, areas of conflict and controversies, and gaps within the relevant literature. When you can clearly observe these things, you will be able to situate your own research and contribute to ongoing debates within the field.
In other words, when reviewing the literature, “not only do you need to engage with a body of literature, you also need to be able to compare, contrast, synthesize, and make arguments with that literature in ways that indicate a readiness to contribute to the literature itself” (O’Leary, 2010, p.81).
* Although the term field is used in this module, please note that some literature reviews address multiple fields of research.
Characteristics of literature reviews
Now that we’ve addressed what a literature review is, let’s discuss what a literature review is not.
What do you think a literature review is, and what is it not? Drag and drop the following statements under the right heading and click 'check' to check your answers.
A literature review should not include every single source that you have read. It’s important to be selective about the sources you choose to address. Ensure the sources you analyse are directly relevant to your research question(s) and topic. It’s important also that you think critically about the credibility and reliability of sources.
Analysis and synthesis
Writing a literature review involves analysing and synthesising previous research.
Analysis and synthesis may appear to be two opposing methods: ‘Whereas analysis involves systematically breaking down the relevant literature into its constituent parts, synthesis is the act of making connections between those parts identified in the analysis’ (Bloomberg & Volpe, 2012, p.84).
In a literature review, however, you will notice the synergy between analysis and synthesis as you zoom-in to closely analyse an individual source, then zoom-out to consider it in relation to the broader field.
After analysing a range of sources, you should synthesise the relevant sources, connecting, linking and positioning them against each other, in order to identify the recurring themes, trends and areas of agreement or disagreement within your research field.
Example of analysis and synthesis
Let’s look at an example of analysis and synthesis. After reading and analysing individual sources, you have identified a key concept relating to your research topic as well as a key resource (A) relating to that concept.
The argument in resource A is supported by another article (B), which is in turn supported by article (D).
However, you have also found article C, which contradicts the argument presented in resource A.
One way to synthesise these texts, is to group together the texts supporting your key resource (articles B and D), and explain that article C presents contradictory results. Then, you would need to examine the methodological differences or any other possible reasons for the contradictory results.
Another way of managing sources and arguments presented in them is to use a literature review matrix (also called synthesis matrix). Literature review matrix is a table in which you can represent the views, ideas, or data according to thematic categories that correspond to your research project.
As you fill out your matrix, you will begin to get a clearer view of how different sources are related, and recognise patterns that may not have been immediately visible before. For example, you may see a correlation between sample sizes and types of conclusions, or between specific kinds of aims and the methods chosen to address them.
Because information is arranged in thematic columns, you can get a useful overview of all aims, or all methods at a glance. You can add new columns as your understanding improves. Thus the review matrix can also be a powerful tool for synthesising the patterns you identify across literature, and for formulating your own observations.
Different types of literature review
Literature reviews exist within different types of scholarly works with varying foci and emphases. Short or miniature literature reviews can be presented in journal articles, book chapters, or coursework assignments to set the background for the research work and provide a general understanding of the research topic.
However, the focus of a literature review in a graduate research thesis is to identify gaps and argue for the need for further research. Depending on the purpose of the writer and the context in which the literature review will be presented, a selective or comprehensive approach may be taken.
In the selective approach, a single or limited number of sources are reviewed (e.g. as in an annotated bibliography assignment, or the introduction of a journal article).
A comprehensive approach requires the review of numerous books and articles (e.g. as in a review article), which can be presented as a substantial chapter in a research thesis or published on its own as a scholarly review article.
(Adapted from Literature Reviews: An Overview for Graduate Students under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 United States license.)
Within a thesis, a literature review may appear in a single chapter – often being the first independent chapter after the introduction. However, reviews of literature may also be dispersed across several chapters, each of which may focus on a different theme, concept, theory or method. As a result, a thesis can contain multiple reviews based upon thematic, conceptual, theoretical and methodological considerations.
The function of literature reviews
What is the purpose of conducting a literature review? What function does a literature review serve within a thesis?
A literature review functions as a tool to:
- provide a background to your work by summarising the previously published work
- classify the research into different categories and demonstrate how the research in a particular area has changed over time by indicating historical background (early research findings in an area) as well as explaining recent developments in an area
- clarify areas of controversy and agreement between experts in the area as well as identify dominant views
- evaluate the previous research and identify gaps (i.e. unexplored areas)
- help justify your research by indicating how it is different from other works in the same area
Even if you’re in the early stages of your research and just beginning to conduct a literature review, it’s useful to consider the eventual role that your review will play within your thesis and the way it functions to orient your readers.
The process of conducting a literature review
Conducting a literature review is an ongoing, non-linear, and iterative process.
“Your literature review will inform your question, theory, and methods, and your question, theory, and methods will help set the parameters of your literature review. This is a cyclical process.” (O’Leary 2010, p.83)
It is usually one of the first tasks that graduate research students undertake, and one of the last to be completed. A literature review written in the early stages of research is likely to change because you need to review and revise it from time to time and ensure it is up to date.
You will probably find yourself engaging with the literature in different ways at different stages of your research.
Each of the stages mentioned above involves three main steps:
- locate relevant literature,
- review the literature, and
- write about the literature.
After selecting a topic to investigate, you will begin to locate and read sources. Then you will analyse, evaluate and synthesise the texts before organising them into a logical structure that you will use to write your literature review.
This is a cyclical, iterative process in that you will return to find and read more sources and incorporate them into your synthesis.
While many of the general considerations outlined in this module are pertinent to all research, there are some particular things to consider when writing a literature review within your discipline. In the following sections, you will find additional information and advice for writing a literature review within specific disciplinary areas.
Practice-based research often leads to the production of a creative artifact, a body of work or a performance, as well as an accompanying exegetical text. If you are writing a literature review as part of a practice-based exegesis, the content within this module will be relevant to you. However, it’s important to note that, to some extent, your literature review is likely to deviate from a typical literature review.
With a focus on creative practice, your research may not necessarily be guided by an explicit research question or a gap that your research aims to address. Nonetheless, a literature review should still contextualise and situate your practice, processes and/or work.
This involves identifying and discussing the key concepts, ideas and theories that are relevant to your research. In addition, it involves analysing the relevant practices, processes and/or work of other practitioners, whether they be architects, artists, designers, musicians, performers, writers or other key practitioners and researchers.
Humanities theses are generally divided into chapters which each deal with an aspect of the research problem. There is usually also a short literature review in the introduction, to situate and justify the study, but often further appropriate research literature is integrated into each chapter. You can see an example of where literature is dealt with in the annotated humanities example on the Thesis structure page.
In disciplines which use footnotes for referencing, some of the literature analysis is carried on in the footnotes, in parallel to the main argument in the text above, as can be seen in the example below, from a history thesis.
This is reflected in scholarship that deals with predestination. Historians and theologians tend to focus primarily on its place within Protestant thinking and its role in the Reformation, generally seeing the earlier Catholic inheritance as something that began with Augustine and stopped with Aquinas. In particular, scholars have focused on the abstract, speculative aspects of predestination rather than on the body of doctrine and moral instruction that it involved.3
3 The study of predestination very much revolves around attempting to define the concept for a modern audience, or defining it narrowly regarding one particular theological viewpoint (such as Aquinas or Calvin). In doing so, scholars focus on only the historical facets of predestination doctrine which are applicable to their own view of the concept. Most works on predestination look at the Protestant concept, with others examining a strict orthodox Catholic interpretation. For an example of this singular focus (in this case, Protestant), see, Peter J. Thuesen, Predestination: The American Career of a Contentious Doctrine (Oxford: Oxford University Press, 2009); for an example of focusing on one particular theologian, see, Michał Paluch, O.P., La Profondeur de l’amour divin: Évolution de la predestination dans l’oeuvre de saint Thomas d’Aquin (Paris: J. Vrin, 2004).
Science and technology
In scientific and technical disciplines, including medicine and health sciences, the literature review is often more narrowly framed around a specific discipline or research area than in the humanities.
A successful scientific literature review will not only identify the current gap in knowledge, but also position your own research project as a viable way of addressing it. You thus need to build a solid argument to convince the reader that
your theoretical and methodological approach is likely to result in a worthwhile contribution to knowledge.
In writing the review, it is important to identify the overarching themes that show you have a thorough grasp of the big picture, and to ensure your observations are supported by sufficient evidence. When reviewing and critiquing existing trends and methods, consider their design, scale and scope, and point out where findings are not comparable or are difficult to compare.
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