The 50 most common PhD viva questions (also known as thesis defense questions) with practical advice on how to approach each one. Prepare with confidence for your viva voce or dissertation defense.
Your viva isn't a memory test. It's a conversation about your research, and the examiners genuinely want to hear you talk about it. But knowing what's likely to come up – and having thought through how you'd respond – makes the difference between walking in nervous and walking in ready.
These 50 questions cover the ground most vivas share. Some will land word-for-word. Others will come at you sideways. Either way, if you've done your prep, you'll have the building blocks for almost anything they throw at you.
A note before we start: there are no 'correct' answers here. Every thesis is different. What I've given you is the thinking behind each question – what the [examiners are actually getting at](/blog/what-examiners-actually-look-for-in-a-viva), and how to structure your response so it lands well.
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1. Can you summarise your thesis in a few minutes?
This is almost always the first question, and it sets the tone for everything. Don't recite your abstract. Give a clear, confident overview: what the problem was, what you did, and what you found. Aim for three to four minutes. Practise this one until it feels natural, not rehearsed.
2. What is your thesis about, in plain language?
They want to see if you can explain your work to someone outside your niche. Strip out the jargon. If you can explain it clearly to a non-specialist, you understand it deeply enough.
3. Why did you choose this topic?
This sounds casual but it's really asking you to justify your research focus. What gap did you identify, and why was it significant enough to warrant doctoral-level investigation? Ground your answer in the field – what was missing, what was being overlooked, what needed challenging – rather than personal anecdote.
4. What would you change about your thesis now?
This often comes early and catches people off guard. The examiners want to see critical self-awareness, not perfection. Identify something specific – a section you'd restructure, an argument you'd nuance, a source you'd engage with more – and explain why. Keep it contained. Don't unravel your own thesis.
5. Can you take us through your conclusion?
Examiners often home in on the conclusion because it's where your argument has to land. Be ready to walk through it clearly – your key claims, how they follow from the evidence, and whether you think the conclusion does justice to the complexity of what you found. If there are hedges or qualifications in there, know why they're there.
6. How did you decide on your theoretical framework?
Explain why this framework was the right lens for your research question. What alternatives did you consider, and why did you settle on this one? Examiners want to see deliberate, justified choices – show that you understood the alternatives and made an informed decision.
7. How does your work build on or depart from [key scholar]?
Examiners will name specific scholars and ask you to position your work in relation to theirs. Be ready to explain where your argument aligns with, challenges, or extends their ideas – and why those points of departure matter for your thesis.
8. Where do you sit in the debate between [X and Y]?
Examiners will pick a specific debate in your field and ask you to take a position. Know where your work lands on the key disagreements and be ready to defend that position with evidence from your thesis.
9. How did you conduct your literature review?
Walk them through your search strategy and how you decided what was in scope. This shows methodological rigour even at the review stage. Mention databases, key journals, snowball searches from reference lists – whatever you actually did.
10. How does your work fit within the broader field?
Show that you understand the landscape. Where does your research sit in relation to the key debates, approaches, or problems in your discipline? This is your chance to demonstrate that you haven't been working in a bubble.
11. What was your basis for the methodology you chose?
The examiner wants to know that your method follows logically from your research question. Explain the fit: why this approach was the most appropriate way to investigate what you set out to investigate.
12. What are the limitations of your methodology?
Every method has trade-offs. Name them before the examiners do. Acknowledge what your approach can't capture, and explain why the trade-offs were acceptable given your research aims.
13. How did you ensure the validity/reliability of your research?
This varies by discipline, but the principle is the same: show that you took rigour seriously. Discuss triangulation, member checking, inter-rater reliability, or whatever quality measures apply to your approach.
14. What ethical considerations did you face?
This will be more relevant to the sciences/social sciences, so if you're a humanities grad, you now have 49 questions (sorry ;). So, for the scientists… Even if your ethics approval was straightforward, discuss the ethical dimensions of your work thoughtfully. Consent, anonymity, power dynamics, data handling – show that you thought about these things as a researcher, not just as a form-filling exercise.
15. If you could start again, would you use the same methodology?
This is a maturity question. The best answers show growth: "Yes, because..." or "I'd adjust X because I now understand Y." Avoid saying you'd do something completely different – that undermines the thesis you're defending.
16. How did you select your sample/case studies/sources?
Explain your selection criteria and why they were appropriate. Whether it's participants, archives, datasets, or case studies, examiners want to see that your choices were principled, not convenient.
17. What challenges did you face during data collection?
Be specific and reflective. Every project hits obstacles. What matters is how you responded – did you adapt your approach, and can you explain why those adaptations were justified?
18. How did you analyse your data?
Walk them through your analytical process step by step. Whether it's thematic analysis, regression modelling, or close reading, show that you followed a systematic and transparent process.
19. What are your main findings?
State them clearly and confidently. Don't hedge everything. You've spent years on this – own what you found. Lead with the most significant findings, then fill in the supporting results.
20. Which finding surprised you most?
This is another that is probably more relevant to sciences/social sciences. Examiners love this question because it reveals how well you know your data. A genuine surprise – and your honest reflection on why it was surprising – shows deep engagement with your material.
21. How do your findings relate to the existing literature?
This is where you show synthesis. Where do your results confirm, challenge, or extend what's already known? Don't just list agreements and disagreements – explain what the patterns mean.
22. What is the strongest part of your thesis?
Pick something specific and explain why. This isn't arrogance – it's critical self-awareness. Know where your work is most robust and be ready to explain what makes it strong.
23. What is the weakest part of your thesis?
The classic trap question, but it's also an opportunity. Choose something genuine but manageable – a limitation you've already acknowledged, ideally one that doesn't undermine your core argument. Show that you can assess your own work critically.
24. How would you defend your argument to a sceptic?
Identify the most likely objection to your thesis and address it head-on. This shows intellectual confidence and the ability to anticipate criticism – both qualities examiners value.
25. Were there any findings you chose not to include?
If yes, explain the editorial decision. If no, that's fine too – but be prepared to discuss how you decided what made the cut. This shows awareness of scope and focus.
26. What is your original contribution to the field?
This is the question your entire thesis exists to answer. Be specific: What do we know now that we didn't know before your research? State it clearly, without false modesty.
27. Why does your research matter?
Connect your work to the bigger picture. Who benefits from this knowledge? What problems does it help solve or illuminate? Think beyond the academy if your work has practical implications.
28. How does your work change how we think about this topic?
This pushes you beyond "I found X" into "X means Y for the field." Show that you've thought about the implications, not just the results.
29. How does your contribution compare to [specific recent work in your area]?
Examiners will often name a specific paper or book and ask you to position your work against it. This isn't a gotcha – it's a test of whether you know the current state of the field. If you haven't read it, say so honestly and explain how it relates to what you do know. If you have, explain the points of contact and departure clearly.
30. Has your thinking on this topic changed during your PhD?
It almost certainly will have. Describe how your understanding evolved. This shows intellectual growth and the capacity for self-reflection – both things examiners want to see in a doctoral researcher.
31. Why did you focus on this specific aspect rather than a broader/narrower scope?
Justify your boundaries. Explain what led you to define the scope as you did, and why it was the right frame for answering your research question effectively.
32. How generalisable are your findings?
Be realistic. If your study is context-specific, say so – and explain what can and can't be transferred to other settings. Overclaiming generalisability is a common viva pitfall.
33. Why did you choose these specific time boundaries/geographical boundaries/parameters?
Scope questions often get granular. Be ready to justify not just your broad focus but your specific boundaries – why this period, this region, this population, this dataset. The answer should connect back to what your research question required.
34. How did your research questions evolve during the project?
Research questions almost always shift. Trace the evolution honestly. Examiners appreciate researchers who can adapt their questions in response to their findings.
35. Did your findings answer your research questions?
Be direct. If yes, explain how. If partially, explain what remains unanswered and why. Avoid vague claims – point to specific findings that address specific questions.
36. Why did you structure your thesis this way?
Show that the structure was a deliberate choice, not a default. Explain the logic: why these chapters in this order, and how the structure serves your argument.
37. Walk us through the argument in chapter X.
Examiners will often pick one chapter (or more) and ask you to lay out its argument. This tests whether you can articulate the logic of any part of your thesis on demand, not just the bits you've rehearsed. Know each chapter's core claim and how it's supported.
38. How do you define [key term]?
Know your key terms cold. If you've defined them in the thesis, be consistent with those definitions. If a term is contested, acknowledge the debate and explain your position.
39. Can you explain the connection between chapters X and Y?
This tests whether your thesis hangs together as a coherent whole. Be ready to trace the through-line between any two chapters and explain how they build on each other.
40. What are the next steps for this research?
Have a clear answer. Whether it's a postdoc project, a journal article, or a completely new direction, show that your PhD has opened doors you're ready to walk through.
41. How would you develop this into a publication?
Think about which parts of your thesis are most publishable and where they'd fit. Naming specific journals shows an awareness of your field's publication landscape.
42. What questions has your research raised that you haven't been able to answer?
Every good thesis generates new questions. Discuss them enthusiastically – they show your research is generative, not dead-ended.
43. If you were supervising a student continuing this work, what would you advise them to focus on?
This tests your ability to think beyond your own project. Identify the most promising or urgent directions that follow from your findings.
44. Can you explain how you arrived at this particular interpretation?
This is the examiners testing your reasoning, not just your conclusions. They'll point to a specific claim and ask you to trace the path from evidence to interpretation. Show your working – what the data said, what alternatives you considered, and why you landed where you did.
45. Why didn't you consider [alternative approach/theory/source]?
This is one of the most common examiner moves – proposing something you didn't include and seeing how you respond. If you considered it and rejected it, explain why. If you genuinely hadn't considered it, engage with it on the spot. The worst thing you can do is get defensive.
46. How has your field changed during your PhD?
Show that you've been paying attention to developments beyond your own project. Mention new publications, methodological shifts, or emerging debates that have appeared since you started.
47. What is the one thing you want the reader to take away from your thesis?
Distil your thesis into its single most important message. This is harder than it sounds, and getting it right shows real clarity of thought.
48. Is there a question you were hoping we wouldn't ask?
This is more common than you'd think. If you've got one, you can acknowledge it with a smile and then answer it anyway. Dodging it looks worse than engaging with it.
49. What question would you like us to ask you?
Use this as an opportunity to talk about something you're proud of that hasn't come up yet. Have something ready – a finding, a methodological decision, or a theoretical insight you'd love to discuss.
50. Is there anything you'd like to add before we finish?
Don't say "no" reflexively. If there's a key point you haven't been able to make, this is your moment. If you've covered everything, a simple "I think we've covered it well, thank you" is perfectly fine.
Don't try to memorise 50 scripted answers. That's not how vivas work, and you'll sound robotic if you try. Instead, use this list to pressure-test your thinking. Work through each question, jot down a few bullet points, and pay attention to where you feel uncertain – those are the areas that need more [preparation](/blog/how-to-prepare-for-your-viva-a-comprehensive-guide).
For a full preparation strategy, see our [comprehensive viva preparation guide](/blog/how-to-prepare-for-your-viva-a-comprehensive-guide).
Better yet, practise out loud. Reading your notes silently and defending your thesis verbally are completely different skills. The questions that feel easy on paper have a way of becoming surprisingly difficult when someone's sitting across from you waiting for an answer.
If you want to practise answering these questions with AI-generated follow-ups tailored to your thesis, [see our plans](/pricing).