The viva — the oral defence of your dissertation — is the part of the degree students fear most and prepare for least. That is understandable: after months of writing, the idea of two examiners asking you to justify your work in person feels exposed. In practice, a viva is rarely an interrogation. Examiners have read your dissertation, they usually want it to pass, and their questions are mostly an invitation to show that you understand your own research: why you chose the topic, why you did it this way, what you found, and what you would do differently. Preparation does not mean memorising answers. It means knowing your thesis well enough to discuss it under pressure, having thought through the hard questions in advance, and having rehearsed the experience itself. If you need structured support with the written chapters first, our dissertation chapter help page covers that ground.
Start by re-reading your thesis as an examiner would
Most students have not read their dissertation straight through since submitting it, and the viva may come weeks or months later. Re-read it slowly, with a pen, marking every claim you would challenge if you had not written it: a method choice you never fully justified, a result you glossed over, a conclusion that reaches further than the evidence. Examiners read exactly this way, so your annotations are a preview of their questions. Pay particular attention to the abstract, the introduction’s research questions and the conclusion, because examiners often start there and use them as a map for the rest of the discussion. Re-read your methodology chapter with particular care — sampling, ethics, analysis choices — since method questions are the most common opening in most vivas. If your discussion chapter needs refreshing before the viva, our guide to how to write a dissertation discussion chapter explains how interpretation and limitations should be framed, which is exactly what examiners probe.
Anticipate examiner questions, chapter by chapter
Topic, questions and literature
Expect to justify why this topic, why these research questions, and why this literature. “Why did you choose this topic?” is almost always asked, and a good answer connects personal interest to a genuine gap: what was missing, and why did it matter? Examiners may ask why a key author or study is absent, or why you framed the literature the way you did. Prepare a short answer for each major inclusion and exclusion, and do not be defensive about scope: every dissertation leaves things out, and examiners respect a student who can say plainly why a boundary was drawn where it was.
Methodology and ethics
Method questions test understanding, not memory. Why this method rather than the obvious alternative? What were its limitations, and how did you handle them? How did you choose your sample, and what does that mean for generalisability? What ethical issues arose, and how were they addressed? The strongest answers name the trade-off honestly — “interviews gave depth but a small sample, so I make no claim to generalise beyond this setting” — rather than pretending the method had no weaknesses. If you used a method you would now change, say so: examiners value that judgement far more than loyalty to a choice you no longer defend.
Findings, analysis and contribution
Examiners will ask what your most important finding is, and they will expect a single clear answer, not a tour of every result. Prepare a two-minute version of your contribution: what you found, why it matters, and what is new about it. Expect to be pressed on analysis: why this coding scheme, why this test, what an unexpected result means. If your conclusion chapter draws the threads together, re-reading our guide to how to write a dissertation conclusion will help you state the contribution crisply. And prepare for the question about limitations — examiners ask it in almost every viva, and a candidate who names their limitations before being pushed to looks confident rather than vulnerable.
Run mock vivas, not just revision sessions
Reading about vivas is not preparation; being questioned is. Arrange at least two mock vivas: one with your supervisor, who knows the work and the likely examiner concerns, and one with a friend or peer who does not know the thesis, who will ask the naive questions examiners also ask. Treat each mock seriously: dress as you will for the real viva, sit formally, and answer out loud rather than in your head, because spoken answers under pressure feel very different from thoughts. Ask your mock examiners to interrupt, to follow up, and to ask at least one question you cannot answer — because the real viva will, and you need practice handling that moment. Record the session if you can, and listen back for habits that undermine you: over-long answers, filler phrases, answers that start before the question has finished. A mock viva that feels uncomfortable has done its job; a comfortable one has not tested anything.
Handling “I don’t know” with confidence
Every viva contains a question the candidate cannot answer, and examiners know it. What they judge is not whether you know everything, but how you handle not knowing. The worst responses are bluffing, inventing an answer, or answering a different question in the hope nobody notices — examiners notice immediately, and trust in everything else drops. The strong response has three parts: say so plainly (“I don’t know — I didn’t consider that angle”), show your thinking briefly (“my guess would be… but I would need to check…”), and, where possible, connect it back to the thesis (“that would be a natural follow-up study”). That answer demonstrates exactly the qualities a viva is meant to test: honesty, reasoning and awareness of your work’s boundaries. Practise saying “I don’t know” out loud before the viva, because the phrase feels much harder the first time you say it to an examiner than the fifth time you say it to a friend.
Corrections: what the possible outcomes actually mean
Viva outcomes vary between institutions, so check your own regulations, but the common pattern is: pass with no corrections; pass with minor corrections, usually typographical fixes and small clarifications within a short deadline; pass with major corrections, meaning substantive revisions that an examiner re-checks; referral or resubmission, where the thesis needs significant reworking and a further examination; and, rarely, fail. None of these except an outright pass should be treated as disaster: minor and even major corrections are a normal part of the process, and many strong theses receive them. What matters is listening carefully in the viva to what examiners ask you to change, noting it precisely, and treating the corrections list as instructions rather than criticism. If examiners discuss corrections during the viva, do not argue with them there — ask clarifying questions, note what is asked, and address it in the revision.
Practical advice for the day itself
The practicalities are simple and worth rehearsing. Confirm the time, place and format — in person or video call — and test the technology the day before if it is online. Bring a printed copy of the thesis, your notes and a pen, even if you expect not to need them; having the text in front of you removes the fear of forgetting a detail. Arrive early, dress as you would for a professional meeting, and eat and sleep normally the day before — a viva rewards a clear head more than a final night of cramming. During the viva, listen to each full question before answering, take a moment to think when you need one, and keep answers focused: a concise answer that invites a follow-up is better than a long answer that loses the thread. If you do not understand a question, say so and ask the examiner to rephrase it; that is a normal academic exchange, not a weakness. And remember the examiners are not your enemies: they have given hours to reading your work, and they are in the room because your research was worth examining.
Frequently asked questions
How long does a viva usually last?
It varies widely by institution and level — undergraduate vivas are often short, sometimes under an hour, while masters and doctoral vivas can run considerably longer. Your department should tell you the expected duration; if it has not, ask your supervisor. Duration is not a signal of outcome: a short viva can end in a pass and a long one in corrections, or the reverse.
Do I need to prepare a presentation?
Only if your department asks for one. Many vivas begin with an invitation to summarise your research briefly, so prepare a five-minute spoken summary regardless — aim, method, key findings, contribution — even if no slides are required. If slides are expected, keep them short and visual, and never read them aloud word for word.
What if the examiners disagree with my conclusions?
Disagreement is normal and is not, by itself, a problem. Examiners may challenge your interpretation to see whether you can defend it, not because they have decided it is wrong. Defend your position with evidence from your data and literature, concede points where the examiner is right, and distinguish between a difference of interpretation — which is legitimate academic debate — and an error, which you should acknowledge.
Can I bring notes into the viva?
In most institutions, yes — a copy of the thesis and brief notes are expected, and examiners do not mind you referring to them. Notes should be prompts, not a script: reading long prepared answers aloud sounds evasive and prevents genuine discussion. Check your department’s rules if you are unsure, since a small number of programmes restrict what you may bring.
What happens immediately after the viva?
Examiners usually ask you to leave the room while they deliberate, then call you back to tell you the outcome and any corrections required. You should receive the outcome and the corrections in writing afterwards. If anything is unclear, ask before you leave — it is much harder to clarify a corrections list days later than in the room.
A viva rewards the same qualities as a good dissertation: clear thinking, honest handling of limitations, and the ability to discuss your own work as a researcher rather than recite it. Re-read the thesis, anticipate the hard questions, rehearse them out loud, and arrive rested. If your written chapters still need strengthening before the viva, our dissertation chapter help page is the place to start.