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PhD literature reviews are tricky. That’s why we’ve written about them so much on The PhD Knowledge Base.
In some respects, the literature review is the most important chapter in your entire PhD. That’s because it has three important jobs. First, it is there to situate your study in the wider academic context. Second, it’s your chance to fully educate yourself in your discipline and to show your examiner that you have a complete grasp of all the major debates and discussions in your field. Third, it’s there to provide a succinct, up-to-date account of the state of the art in your discipline. In this post, I want to discuss each of these in turn. In doing so, we answer a simple question: what is the purpose of a PhD literature review?

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Situate your research in the broader a context

The main purpose of a literature review is to situate your research in a broader context.
No academic research exists in a vacuum. Most often, new academic research builds upon old academic research. By reviewing the state of the art, and what existing studies have found, you are able to better understand how your research can build upon it.
It’s important to remember the key purpose of your PhD: to make an original contribution to knowledge of publishable quality. To be able to make an original contribution to knowledge, you need to first tell the reader what knowledge we already have in a particular field, and what gaps exist within it. That is where the literature review comes in.
It’s in the literature review that you highlight the gap that your thesis will then fill. Or, in other words, where you state what contribution your thesis will make.
To highlight the gap in the literature and therefore situate your contribution, you need to first discuss the current state of the art in your niche.
That requires a huge amount of work. By definition, to make the case that a particular gap exists, you need to present a comprehensive picture of what currently exists in order to then highlight what’s missing.
Seen in this way, the literature review is there to set the stage for your own study. It’s there to say ‘here’s everything we already know, and here’s what we don’t know’.  It’s your job in the literature review to convince the reader that the gap you talk about is actually there and that it is a worthwhile endeavour to actually fill it.
If you do those convincingly, your ‘original contribution’ is built on safe ground. If you do it poorly, you may not make a convincing enough case that your contribution is either original or worthwhile.


Make the case for your research


Another job of the literature review is to make the case for your research. It’s there to problematise the existing literature in order to highlight a gap that your research will then aim to fill, driven by your research questions and research aims and objectives.
Your job is to tell the reader what’s wrong with the existing understanding of your topic. It may be that there are methodological flaws, or that there are gaps in our empirical understanding. Or, it may be that the particular perspective or approach taken is somehow problematic. Whatever it is, your job in the chapter is to articulate that problem and then situate your research question as your path to fixing it.
You can think of a person developing a new type of mobile phone. In order to be able to do so, they need to have a good understanding of how old mobile phones are made, principally to understand what problems there are with those existing designs and to see where things can be built upon and improved. Your PhD is the same.
To be able to make an original contribution to knowledge in your field you need to know what it is that your field is discussing and, crucially, what problems there are with those discussions.


Educating you in your discipline 

Beyond making the case for your research, the literature review is also there to make you a better academic. The process of conducting your literature review will educate you thoroughly in your discipline, and give you a rounded understanding of the major debates, theories, concepts and findings.
You’ll need to demonstrate to your examiner that you have a comprehensive understanding of your discipline and that you understand the major debates, seminal texts, key findings, major theories, and so on. The literature review is your opportunity to do that. 

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How does the literature review relate to your research questions? 

You would have told the reader very early on in your thesis what your research questions are. Ideally in the first paragraphs of the introduction chapter.
But in many ways, those research questions only really make complete sense once you have completed your literature review. Despite having presented them in the introduction, it helps to see the research questions as a conclusion of the literature review. That’s because your research questions are your way of filling the gap you highlight, and as we saw above highlighting a gap is one of the core objectives of the literature review.
So, once your examiner has finished reading your literature review, they’ll be able to see what the gap is, why it is important to fill that gap, and, therefore, why your research questions are important.
This obviously means that there needs to be a logical connection between your research questions and the gaps you discuss. They should make sense. The person reading them should be able to clearly understand why those questions will fill the gap you showcase. If the connection isn’t immediately obvious, you’ll need to explain it explicitly. What you want to avoid is a question that is disconnected to the gap. 




Because it is there to highlight any gaps in the literature and justify why filling those gaps is important, and because such contributions are at the heart of any PhD, the literature review is crucially important.
If you fail to adequately make the case that the contribution exists and that it is worthwhile filling it, it doesn’t matter how good the rest of your study is, you will fail to convince your examiner that the study has merit and that you have made a sufficiently robust contribution to knowledge.
Beyond that though, the literature review serves as a foundation upon which the rest of the thesis is built. Once you have made the case in the literature review that a gap exists and that it is worthwhile filling it, you are able to explain how you will fill that gap (in your theory framework section/chapter, and then your methods section/chapter). Once that is out of the way, you present your empirical data as a way of filling that gap, and then really nailing home its significance in the discussion and conclusion chapters.
But it all stems from the literature review. Fail to make the case that a gap exists, or that it is worthwhile filling it, or fail to show the examiner that you have a sufficient grasp of the debates and themes in your discipline and your thesis will be sent back for corrections.
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PhD Literature Review & Theory Framework Survival Pack

Master your lit review & theory framework.

Learn what goes where (and why), and how it all fit together with this free, interactive guide to the PhD literature review and theory framework.