How to Write a Research Gap for Your Thesis

A research gap is a specific thing that existing studies have not done, and that your study will do. When a committee writes "your literature review lacks a clear gap," it means the review shows what others found and never says what is missing.

The gap is the reason your study exists. If the reader cannot say what it is after Chapter 2, the study has no justification.

What a gap is not

A gap is not a topic nobody has written about. Almost every topic has been written about, and a claim that "no research exists" is usually wrong and easy for a committee to disprove. A gap is also not a list of things you found interesting.

Four kinds of gap

A missing population. Studies exist, but not on your group, place or level. Example form: researchers have studied the topic among one group, and none has studied it among yours.
A missing method. Studies exist, but all use the same approach, such as surveys, and none explores the experience through interviews.
A conflict. Studies disagree, and the reason is not settled. Your study can test a possible explanation.
An outdated finding. The key studies are old, and conditions have changed.

State which kind yours is. It tells your reader what kind of contribution to expect.

How to find it in your sources

Build a table with a row for every study you cite. Columns: author and year, population, method, main finding, stated limitation.
Read down the columns. If every study uses the same population or method, that is a pattern. If findings disagree, that is a conflict.
Read the limitations and "future research" sections of the strongest articles. Authors often name the gap for you, and you can cite them for it.
Check that the gap is real. Search for the combination you claim is missing. If you find a study, change the claim.

Our guides to organizing sources by idea and to judging whether your review is good enough show where the gap belongs in the chapter.

How to write it

State the gap in one or two sentences near the end of the review, in plain words:

Studies by [Author, year] and [Author, year] examined [topic] among [population] using [method]. None has examined [what you will study], which leaves [what is not known]. This study addresses that gap by [what you will do].

Fill the brackets from your own sources. The citations must be studies you have read, and the claim must match what they did.

Carry the gap forward

The gap should reappear, in the same words, in your problem statement, your purpose statement, your research questions and your discussion. If it changes from chapter to chapter, the committee will notice. See writing the problem and purpose statements and what Chapter 2 should include.

Why committees push back

The usual causes are a gap stated too broadly ("little research exists"), a gap not supported by the sources, and a gap that does not lead to your research questions. Test yours: does each research question follow from the gap?

Want a reader to test your literature review?

The Two Dissertation Moms offers a Dissertation and Thesis Chapter Review that checks whether your literature chapter builds an argument and names a gap your questions can answer.