What questions does the committee ask in a thesis defense?

Most committee questions come from the thesis itself: members ask about the places where they made notes in the margin. So you cannot know every question in advance, but you can know which kinds will come. How long the defense lasts, how many people sit on the committee and the order of questions differ between institutions; check your own graduate school’s regulations for those. The types below, however, come up in almost every field.

1. Contribution: "What does this thesis change?"

The first thing a committee wants to know is what your thesis adds to the field. This question often looks the easiest and turns out to be the hardest, because students describe what they did without saying why it matters.

• Can you state the contribution of this work in two sentences?
• If this thesis had not been written, what would we not know?
• Which of your findings is the most important, and why?

A good answer names the gap in the literature, what the thesis brings to it and who that matters to. Saying "no one has studied this" is not enough; you need to show why the gap is worth filling.

2. Method choice: "Why this method?"

Method questions target the reasoning behind your choice more than the choice itself. The committee will ask why another route was not taken and which assumptions your route relies on.

• Why did you choose a quantitative rather than a qualitative design (or the reverse)?
• How did you select your sample, and what does it represent?
• How do we know the instrument is valid and reliable in this sample?
• Did you test the assumptions of your analysis, and what would you have done if they failed?

A good answer ties the choice to the research question, names the alternative you considered and explains why you ruled it out. For the gaps committees most often find, see the methods chapter guide.

3. Limitations: "How far does this result hold?"

When committees ask about limitations, they are not trying to corner you; they want to see whether you know where your conclusions stop. Denying a limitation and conceding every criticism until the thesis seems worthless are two separate mistakes.

• What do you think is the biggest weakness of this study?
• Can these findings be generalised to another city, age group or period?
• How might relying on self-reported data have affected your results?

A good answer acknowledges the limitation openly, says in which direction it could bias the results and shows which conclusion still stands despite it.

4. Alternative explanations: "What else could it be?"

The toughest questions about interpretation are of this kind. The committee suggests that another mechanism, a confounding variable or a measurement problem could produce the same result.

• Is there a third variable that could explain this relationship?
• Could the difference be due to baseline differences between the groups rather than the intervention?
• Can you draw a causal conclusion from a correlational analysis?

A good answer takes the alternative seriously and says how far your data rule it out, or fail to. If you cannot rule it out, saying so and narrowing your claim looks stronger than defending it. The discussion chapter guide helps you write that chapter with these questions in mind.

5. Literature: "How does this fit with earlier work?"

Literature questions come from two directions: whether you missed an important study, and how you relate your findings to previous ones.

• Your finding contradicts X’s study; how do you explain that?
• Why did you not engage with this approach in the field?
• Why did you choose this theory as your framework?

A good answer tries to explain a contradiction through differences in method, sample or context, and if a study was missed, admits it and discusses how it would affect the findings.

6. Future work: "What should come next?"

Usually asked towards the end, this question tests whether you can see the next step beyond your thesis. "It could be repeated with a larger sample" is a very common answer and weak on its own.

• If you wrote this thesis again, what would you do differently?
• Do your findings have implications for practice or policy?
• What question should the next study ask?

A good answer proposes a concrete question that grows out of your own limitations and says which method could answer it.

Detail questions come too

Alongside the big questions, the committee may ask about a specific number in a table, the definition of a term or why a particular source was used. Small inconsistencies, such as a value in a table that differs from the one in the text, shake the committee’s trust in the rest of the thesis. Knowing your thesis well, down to page numbers, matters as much as preparing for the big questions.

How can you predict which questions will come?

Reread your thesis the way the committee will, looking for weaknesses, and note every place you are unsure of: a decision without a stated reason, an interpretation the data cannot carry, a contradiction left unexplained. Those notes are the core of your list of likely questions. Share the list with your advisor or a peer from your field and rehearse the answers out loud. For a preparation timeline, see the guide on how to prepare for a thesis defense.

tezkeys reads your thesis chapter by chapter and builds this list for your thesis specifically: the questions your committee is likely to ask, which of them are hard and what a good answer should cover. In the defense rehearsal you can answer those questions and get feedback. The report is generated by AI and can be wrong; it does not replace your advisor or committee. You can see what it looks like in the sample report.