Thesis Defense and Viva Questions to Prepare For
The questions examiners ask in a thesis defense or PhD viva, from contribution to limitations, and how to answer when they point at a single line.
What do examiners ask in a thesis defense?
Examiners usually open broad: summarise your thesis and say what it contributes. They then go into detail on your method choices, a specific claim, your limitations and the literature you used or left out. They close on the future: what you would do next and what you would change if you started again.
The examiners have read every page. They are not checking whether you wrote it; they are checking whether you understand why each decision was made and where the work stops. University guidance says the same: examiners challenge you to help you defend the work, not to fail you, and you know your subject better than anyone in the room (University of Reading).
Format varies. Prospects describes most UK vivas as two examiners, one internal and one external, sometimes with an independent chair (Prospects). Vivas can be in person, online or hybrid, as the Warwick viva FAQ notes. A master's defense is usually shorter and lighter on literature, but the stages below still apply.
Questions by stage of the defense
Grouped by what the examiner is trying to find out. Themes drawn from university and NIHR viva guidance; the wording will differ in your room.
| Stage | What they want to know | Typical questions |
|---|---|---|
| Opening | Settle you in and hear your own framing |
|
| Methodology | Check that your choices were deliberate |
|
| Findings | Test whether the claims follow from the evidence |
|
| Limitations | See whether you know where the work stops |
|
| Literature | Place the work in its field |
|
| Future | Close on direction and confidence |
|
For more sample questions by theme, the NIHR Dementia Researcher viva guide lists questions on ethics, contribution and generalisability.
Answering about weaknesses
Every thesis has limits. The examiner wants to see that you know yours. Use three moves: acknowledge, explain why, extend.
Acknowledge
"Yes, the sample is drawn from a single region, and that limits how far the findings generalise."
Explain why
"Access to the clinics was the constraint; I chose depth in one region over a thinner national sample."
Extend
"A follow-up in a second region would test it. Chapter 6 sets out what I would expect to change."
Adapt the example with your own facts. The trap on either side is the same: defending a real weakness as if it were not one, or conceding so much that the contribution disappears. Concede the limit, keep the claim inside it, and show you know the next step.
When the examiner points to one sentence
At some point an examiner will turn to a page and read a line back to you. It is the moment most candidates fear, and it has a routine.
- Pause and find it. Turn to the page in your own copy. Taking ten seconds is normal and expected.
- Reread it, and the sentence before. Context often answers the challenge.
- Ask what concerns them if it is unclear. "Is your concern the wording or the inference?"
- Justify or concede. Either point to the evidence that supports it, or say "That is worded more strongly than the data allow; I would revise it to..."
Conceding an overstated sentence is a small correction, not a crisis. Arguing for it when it is wrong costs far more.
A two-week viva preparation plan
Based on university viva guidance: reread, summarise, tab, rehearse aloud, then rest.
Days 1 to 4
- Reread the whole thesis once, straight through, as an examiner would
- Note typos and errors on a separate sheet; prepare a short correction list
- Write four or five key findings per chapter on one page
Days 5 to 8
- Tab key chapters, figures and tables in your copy so you can find them in seconds
- Write draft answers to the likely questions in the table above
- Read recent papers in your area and your examiners' relevant work
Days 9 to 12
- Hold a mock viva with your supervisor or a colleague who has a doctorate
- Practise a two to five minute spoken summary until it is natural
- Rehearse your answers to the weakest point in the thesis out loud
Days 13 and 14
- Check the format, time, place or link, and your institution's regulations
- Stop rereading; rest, sleep and eat properly
- Pack your annotated copy, the correction list and water
Anxiety peaks in the last few days. If it is getting in the way, the interview anxiety page has practical techniques, and building interview confidence covers the longer game.
Run a mock viva out loud
A supervisor mock is the gold standard. Extra rounds between them help you rehearse the routines above.
The academic interview scenario on VirtualInterview.ai has a thesis defense or viva mode. You name your field and paste your abstract, and an AI committee member questions your actual work. Its follow-ups challenge the claim you just made: the evidence, the assumption behind it, a counter-example or the limitation. You can make it supportive, fair or the sceptic on the committee.
The report scores Subject knowledge, Reasoning, Clarity of explanation, and Motivation and fit, with feedback on each answer. It cannot read your whole thesis the way an examiner has, so treat it as rehearsal for the routines, not a substitute for your supervisor's mock. Scores are estimates, the camera is a mirrored self-view that is not recorded or analysed, and it does not help during a real viva. A free account includes 2 practice sessions a month, with a full report on your first interview and a preview after that.
Earlier in the journey, the same scenario runs PhD admissions interviews. For a committee of several, see the panel interview practice page.
Frequently asked questions
- How long is a PhD viva?
- It varies by institution and discipline. Prospects puts the typical range at one to four hours with most around two, and the University of Warwick history department says usually half an hour to two hours. Your examiners or graduate school can tell you what to expect.
- What is the first question in a viva?
- Often a broad one: summarise your thesis, tell us why you chose the topic, or what your main contribution is. Prepare a two to five minute spoken summary that ends on your contribution, so the opening sets the agenda you want.
- Can you fail a thesis defense?
- It is possible but uncommon. Typical UK outcomes include a pass, minor corrections, major corrections, resubmission, the award of a lower degree such as an MPhil, or no degree. Being asked for corrections, even major ones, is a normal result and a chance to strengthen the work, not a failure.
- How do I prepare for a mock viva?
- Ask your supervisor or a colleague with a doctorate to read key chapters and question you for an hour, including on your weakest section. Treat it as the real thing: sit at a table, use your annotated copy and answer aloud. Write down every question afterwards and redraft the answers that felt thin.
- Can I bring my thesis into the viva?
- Usually yes. Many UK universities expect you to bring a copy, and annotating it with tabs and short notes is common. Check your own institution's regulations for what annotations are allowed.
- What is the difference between a viva and a thesis defense?
- Both are oral examinations of a thesis. In the UK the viva is usually a closed discussion with an internal and an external examiner and is described as more of a dialogue than a defence. In North America a defense often starts with a public talk followed by questions from the committee.