Literature reviews: An overview
A literature review does not only summarize what has been written about a topic already: it also offers a critical analysis of the existing literature.
Literature reviews can take different forms depending on what type of research you are doing and what your field of research is about. Literature reviews are a key part of the majority of academic articles or theses, and can even be written as articles all on their own. A literature review does not only summarize what has been written about a topic already: it also offers a critical analysis of the existing literature. In other words, you, the author, offer your analysis or critique on what has been written already. A literature review, however, should not just be a description of what has been written or a set of summaries.
The idea of reviewing and analyzing all the research that has been done on a topic can sound overwhelming; however, the task is easier than it sounds. This is also a vital step in performing the work necessary to write a good thesis. As you prepare and write your literature review, you will select and filter which sources are relevant to your work and which are not. As you review the literature, you will develop a clear understanding of the work that has come before you. This will enable you to write about it in such a way that you clearly demonstrate how you arrived at your own thesis statement or hypothesis.
A literature review can be quite short (5% of a paper) or quite long (30% of a paper) depending on the type of paper. For a thesis/dissertation, a literature review may be a full chapter, and is usually at least 10-20% of your paper.
Types of literature reviews
There are different types of literature reviews and the type you choose will be determined by the topic you are researching. Four common types of literature reviews are summarized below, but there are also other types that may be preferable depending on your thesis topic.
Chronological
This type of literature review organizes sources and their ideas by the date of publication. For example, if you are writing about chronic Lyme disease, you would start with articles describing and identifying Lyme disease (1970s), then describe initial treatments and discoveries (1980s), increased prevalence of Lyme disease and rise of people with chronic Lyme disease (2000s), and finally discuss the current controversies and treatments (2010s).
Trend
This type is often used in social science papers such as political science or public policy. They focus on specific trends in a field and can still include a chronological component. For example, you could write about changes in approaches to early childhood education by discussing the rise and fall in popularity of public preschool, highlighting relevant case studies, and presenting arguments that there is no need for schooling so early. This is often used to highlight competing schools of thought in a field.
Methodological
This focuses less on what is said in different sources and more on how previous research has been performed. For example, a methodological review of the treatment of chronic Lyme disease might reveal that previous studies which relied solely on laboratory tests dismissed persistent Lyme symptoms as “all in the patients’ heads,” while studies that focused on interviewing patients as well as doctors classified the disease as an unidentified syndrome. Methodological studies can highlight how approaches to research have changed over time and how the approaches used in research influence the results.
Theoretical
Theoretical literature reviews are often found in fields like philosophy or humanities, but are also prevalent in social sciences. They review existing theories and their relationships, as well as what has been tested and what has not. This kind of review is quite useful in demonstrating where existing theories fall short in describing a particular phenomenon in the field.
Structuring your literature review
A literature review is usually a chapter in your thesis/dissertation and as such generally includes an introduction, main body, and conclusion. The introduction will explain:
- The type of literature review you have performed
- Why you have chosen to perform that type of literature review
- Your criteria for selecting sources
Your main body will be the actual literature review, which we will discuss further in the next section. In your conclusion, you will summarize the major arguments that you have highlighted in your literature review and center your own research among them. The conclusion of the literature review should explain why your research study is necessary (what gap in the literature it fulfils) to lead smoothly into your next thesis chapter.
How do I review the literature?
An easy way to find relevant sources is to look at the citations of papers you find that are on the topic you want to research.
Before you write a literature review, you need to:
- Become familiar with the literature
- Select which sources are relevant to your thesis topic
- Organize your sources
- Choose the type of literature review you will write
- Arrange your notes to reflect the type of literature review
How do you become familiar with the literature?
If you aren’t sure where to start, try going to Google Scholar and typing in some keywords about your topic. For example, if you’re researching chronic Lyme disease, you could type in keywords such as “chronic Lyme” “post-treatment Lyme disease syndrome” and “Lyme disease treatment” to see what results show up. As you search, you will be able to identify more keywords that are relevant to what you want to search. Making a list of these keywords can help you as you engage in this task. When you find an article that looks promising, copy the citation information from Google Scholar and save it in a file or use a reference manager like Mendeley. You will thank yourself for this later. You can then search your academic institution’s online library to download the article.
An easy way to find relevant sources is to look at the citations of papers you find that are on the topic you want to research. If you aren’t sure whether an article or paper you are reading is reputable, you can check its citation metrics using Google Scholar, which can tell you how many other people cited a particular source. Generally, it holds true that the more highly cited a source is, the more reliable and useful it is. Of course, your citation sources don’t need to be limited to journal articles. Books, news articles, interviews, and other sources are all acceptable.
Finally, as you read through sources and organize them, you will want to take notes. Don’t just save an article and hope you’ll remember why you did. Jot down a few sentences about the main argument of this source and why/how it is relevant to your research study. Once you have done this, you will want to go ahead and organize your sources in an order that reflects the type of literature review you have chosen to do. For example, if you are doing a thematic review, you should organize sources by a theme or type of argument. If you are doing a historical review, you would organize them in chronological order.
Writing the literature review
As you write your literature review, you will want to walk the reader through what has happened in the literature review and offer your analysis of it.
Now that you’ve reviewed the literature, taken notes, organized your sources and your notes, you are ready to begin! As we mentioned above, a literature review needs an introduction and a conclusion. As you write your literature review, you will want to walk the reader through what has happened in the literature review and offer your analysis of it. For example, you could say “while Yue and Xu argue that Lyme disease is a bacterial infection and should not result in symptoms resembling post-viral syndromes, others such as Scott and Zebrowski have noted the strong similarities between patients with chronic Lyme disease and the newly emerging group of COVID long-haulers. Scott and Zebrowski appear to be at the forefront of the changing perspective on chronic Lyme disease as newer evidence supports their position.”
Your literature review will include the ideas of many other people, but it should not be a lengthy chapter directly quoting other papers. You should instead paraphrase what others say. Of course you can use some quotes! They are not off limits. Short quotes like “Marx said ‘religion is the opiate of the masses’ while Mao Zedong said ‘religion is poison’” is fine. Longer blocks of text should be used only when necessary and properly indicated within the text.
Now you are ready to write your thesis literature review! Check out our site for more tips on how to write a good thesis, where to find the best thesis editing services, and more about thesis editing and proofreading services.