Q: How do I identify a research gap during the literature review?

Specifically in the context of doing and writing the literature review, you can identify a gap in any/all of the following ways:

• Look up papers that build on previous papers, be it by the same author/s or others. Find out what gaps the later papers have addressed, and if there are still any.
• On the same lines, you may also wish to go through papers cited by the present paper.
• Go through the Discussion/Conclusion section of the paper, where the author(s) talk(s) of the shortcomings of their research and suggest ways in which they think their research could be improved in the future. Also go through the implications and recommendations mentioned (if any) in case there are any ideas there.
• Finally, it also comes down to your knowledge of the topic you are studying and your research acumen, your astuteness in being able to identify a gap that could lead to a potential study of considerable significance/impact. This, as you can gauge, will come with time.

For now, here are some resources for further help with your question.

• How does a problem statement lend itself to further inquiry on confirming a gap in research?
• How can I describe the gap in literature when no previous research has been done on the problem?
• Would my work be considered addressing a research gap or making a contribution?

And here are some resources for help with writing a literature review.

• What a journal editor expects to see in a literature review
• How to write the literature review of your research paper

And in case you’re presently writing a review paper, all the best!