Literature Review Problems: How to decide what NOT to include in your literature review!

A common literature review problem is knowing what NOT to include.

How do you decide what literature you're leaving out? Where do you draw the line?

You can't review all of the literature, right?

How do you justify excluding a body of literature from your literature review that's kind of related but not directly relevant?

When it comes to your literature review, knowing when to stop and what not to include is just as important as knowing what to actually put in.

If you end up including a load of unnecessary literature, “just in case”, your literature review is going to end up really cluttered and really fragmented. You'll end up sacrificing depth for breadth. So, what can you do during the process of developing your literature review to make sure that doesn't happen?

Well, keep reading because I'm going to tell you. If we've not met before, hi, I'm Dr Elizabeth Yardley and in the 20 years that I've been supporting graduate students, the literature review has been the chapter that people have struggled with the most.

It's no surprise because it's a crucial part of your thesis. It's the foundation upon which you build your contribution to knowledge.

There are a lot of things to pay attention to in a literature review. So, how do you ensure it's super focused?

Aims, objectives and research questions

Firstly, you need to pay attention to your aims, objectives and research questions. They are your North Star. They are your guiding light in this vast choppy sea of literature. Whenever you feel lost or overwhelmed, take a look at them.

They're going to help you stay focused. They're going to ensure that your literature review remains relevant.

Because we've all been there, haven't we? We've all gone chasing after some shiny book or study, thinking it's amazing. Then we've found all the books and all the articles that have cited it, and we've been like, “Oh, how interesting!”.

We've written up some lovely notes on it.

And then we have really struggled to integrate that stuff into our literature review. You know why that is, don't you? Because all of that shiny stuff, interesting as it was, was not directly relevant or important to what we're actually doing!

Aims, objectives, research questions. They are going to give you a poke and remind you of exactly what it is that you are doing. And whilst they probably won't stop you going down every single literature review rabbit hole - because that's a bit of a PhD rite of passage - they are going to be helpful for avoiding a few of them.

You should be able to link every piece of literature you review back to your aims, your objectives, or your research questions. You should be able to say, “Okay, this - this thing that I'm reading relates to my second research aim”.

“And this thing provides some useful context for this research question.”

If you're feeling a bit meh about your aims, your objectives, your research questions, I would strongly advise you to put your literature review down for a while and go and take a look at them.

Spend a little bit of time revisiting them, making sure they're clear, making sure they're focused, and there's a blogpost right here to help you do that.

Map out the literature into core, peripheral and related

Secondly, it can be really helpful to map out your literature. Create a visual map of it. This could be a mind map, a flowchart, or just a simple list.

Categorise the literature into core, related, and peripheral.

Core literature directly addresses your research questions.

Related literature provides context or background information.

Peripheral literature is interesting but not essential.

This map is going to help you see the connections between different studies and identify gaps or overlaps.

It'll also make it easier to decide which studies are the crucial ones and which ones you can leave out.

Regularly review your literature map. As you read more studies, as you develop your knowledge of this area, you might find that some of those peripheral studies are actually becoming more relevant.

You might also find that some of what you categorised as core literature in the beginning becomes less important. Adjust that map accordingly as you come to learn more about your topic.

Remember, not all studies are created equal. Some will have a significant impact in your field, whilst others will be less influential.

Focus on the high impact studies, the ones that are frequently cited and the ones that have shaped the direction of research in your field. By including these studies, you're building on established knowledge and they're the studies your examiner is going to be expecting to see when they look at your work.

Setting and justifying literature review boundaries

One of the challenges of writing a literature review is justifying why you chose to include some studies and exclude others.

Here you need to be transparent about your criteria. Explain your inclusion and exclusion criteria clearly. This demonstrates that your approach to selecting literature is a strategic one.

For example, you might include studies that directly address your research question, provide strong evidence for or against what you're arguing, and studies that are widely cited and considered foundational in your subject area.

Conversely, you might exclude studies that are only loosely related to your topic provide weak or inconclusive evidence, and are not highly cited or are considered quite peripheral in the field.

Be clear about the limitations of your literature review. No literature review can cover everything. State that whilst every effort was made to include relevant and important studies, some literature might have been excluded due to constraints on your scope. This kind of transparency shows that you are aware of the limited breadth of the research.

For each collection of studies or chunk of the literature you excluded, provide a rationale for that. For example:

• This study was excluded because it focuses on a different demographic not relevant to my research questions.

• While this study provides interesting insights, it does not directly address the core questions of my dissertation.

• Whilst this area of the literature has become increasingly prominent in recent years, it is not pertinent to include it in this literature review because…

Review, record, revise

Your literature review is not a static document. It evolves as your research progresses, so you need to be prepared to revisit it and refine it as you go along.

Maintain a running list of literature that you come across during your research. This list should include the studies that you have incorporated into your literature review and the ones that you haven't. It should also include notes on why they were included or excluded.

This not only helps you stay organised, it provides a clear record of your decision making process. This does not have to be onerous or detailed! A simple list or another couple of columns in an existing spreadsheet will be absolutely fine.

You'll be able to scan through it from time to time, and it is particularly helpful if you find that the focus of your study is shifting. So, whilst that book about, say, social control theory, was not relevant six months ago, recently, you might have shifted the focus of your study, and that might bring social control theory back into your ballpark.

Be flexible, be open to new information. As your research progresses, you might need to revisit that inclusion and exclusion criteria. Stay adaptable. Remember, your literature review is a tool to support your research. Remember, the aim of your literature review is to is not to include absolutely every single study.

It's about demonstrating your knowledge of the relevant existing literature. It's about building a foundation upon which to construct your study.

Found this blogpost helpful?

If you found this blogpost helpful, you might want to binge my other posts about all things literature review - here’s the link to do that - happy reading!