How many sources should a literature review have?

No rule gives one number that applies to every literature review. The count depends on your level, your field, how wide your question is, and what your program expects. Students who search for a number usually find one that belongs to someone else's study.

The better question is whether your sources cover the debate your project sits in. A review with sixty well-chosen sources can serve a master's thesis better than one with two hundred loosely related ones.

What decides the number

• Level. A doctoral dissertation reviews more literature than a master's thesis, because it must show command of a field.
• Field. Reference lists in the sciences, education, nursing, and the humanities follow different habits.
• Width of the question. A narrow question needs fewer sources than a broad one. A broad question also draws a comment from your supervisor, as we explain in what to do when your research question is too broad.
• Your program's rules. Some handbooks state a minimum or a range. Read yours before anything else.

How to find your program's real range

Ask your supervisor first. A direct question works: "Roughly how many sources do students in this program cite in the literature review?"

Then check for yourself. Open your university's thesis or dissertation repository, pick three recently approved works from your own department, and count the references in each literature review chapter. Those three figures are the standard your committee has already accepted, and they are far more useful than a number from a blog or a forum.

What the sources must do

A count tells you nothing unless the sources are the right ones. A strong review includes:

• Current research. Most of your sources should come from the last five to ten years, though the window depends on how fast your field moves. Ask your supervisor.
• The foundational works. Older studies and theories that your field still cites belong in the review, even when they fall outside the recent window.
• Peer-reviewed work as the core. Books, reports, and official data can add context, but journal articles carry the argument in most fields.
• Opposing views. If researchers disagree about your topic, the review shows both sides.

Signs you have read enough

You can name the main positions in the debate and the researchers behind each one. New articles keep repeating points you already hold, and you can predict what they will say. You can state the gap your study fills in a single sentence. When all three are true, more reading adds little.

Signs you have not

You cannot say where researchers disagree. Your sources all come from one country, one decade, or one research group. Your gap is a guess and not something the literature shows.

The mistake that matters more than the count

A review organized one source at a time reads as a list of summaries, whatever the number. Organize by idea instead: group sources by what they argue, compare them, and say what the comparison means for your study. Our guides to organizing sources in a literature review and to judging whether your literature review is good enough walk through both.

Do not pad the review with weak sources to reach a figure. A committee reads the argument, and a thin source stands out.

Want a reader to check your literature review?

The Two Dissertation Moms offers a Dissertation and Thesis Chapter Review that tests whether your literature chapter builds an argument and points to the gap.