How a viva is structured
A viva voce typically follows a consistent format, though the specifics vary by institution and program. Here are the standard elements:
- Two examiners: One is internal to your institution (usually knows the thesis already); the other is external and specializes in your field. Both hold doctoral degrees and have published research in your area.
- Closed-door format: Unlike many US defenses, which are open to the public, a viva is private. Only you, the examiners, and sometimes a supervisor (who is silent) are present. This is not a performance or public lecture.
- Duration: Most vivas last between 1.5 and 3 hours, with 2 hours being common. The clock starts when the examiners are ready and ends when they dismiss you.
- No formal presentation: Many vivas have no slide presentation component. You walk in with your thesis—the examiners have usually read it—and they begin asking questions. Some programs allow or require a brief 10–15 minute overview, but this is not universal.
- Live correction: You are expected to defend, clarify, and sometimes concede weaknesses in real time. You cannot leave to research an answer or come back later.
After the viva, you leave the room while examiners confer on the outcome, which is communicated to you within days or weeks.
US defense vs UK viva
While both are oral exams of doctoral research, the US defense and UK viva differ in key structural and procedural ways:
| Feature | US-style committee defense | UK-style viva voce |
|---|---|---|
| Audience | Often public; department members and colleagues may attend | Private; examiners and candidate only (sometimes supervisor) |
| Panel size | 3–5 committee members (chair + advisors + internal/external readers) | Exactly 2 examiners (1 internal, 1 external) |
| Presentation component | Candidate typically opens with a 30–45 minute talk, then takes questions | No formal presentation in many cases; mostly conversational questioning |
| Format | Structured: talk, then Q&A, usually with time limits | Fluid and conversational; no fixed agenda or order |
| Outcome categories | Pass (often immediately), fail, or conditional pass (rare) | Pass no corrections, minor corrections, major corrections, new viva, fail |
Both are summative: they assess whether your thesis meets doctoral standards. But the US model emphasizes public scholarly exchange; the UK viva is a rigorous private examination.
Possible outcomes
Viva outcomes are typically coded by the academic regulations of your university. Here are the standard categories:
| Outcome | What it means |
|---|---|
| Pass (no corrections) | Your thesis is awarded as submitted. Rare but it happens. You are done. |
| Pass with minor corrections | Most common outcome. You fix small things (typos, clarifications, minor rewording, citations) within a set deadline (often 6–8 weeks). You submit the corrected version to your supervisor or a designated examiner for sign-off. Thesis is then awarded. |
| Pass with major corrections | Examiners want substantial revisions—new analysis, additional experiments, major rewriting of sections. You revise and resubmit for re-examination. May involve a second viva. |
| Referral for new viva | The examiners are undecided after the first viva. You are asked to revise specific parts and return for a second viva. Less common than major corrections, more definitive than minor. |
| Fail | The thesis does not meet doctoral standard and cannot be fixed by revision. You do not get a doctorate. Rare. Usually this is called "Not Approved" or "Referred for Resubmission" (which may be a path to try again the next year). |
Minor corrections is reported in most UK guidance as the most common outcome, though exact frequencies vary by institution, discipline, and department selectivity. Check your own program's handbook for historical data and success rates.
How to prepare
Preparation for a viva is active and deliberate. Here is what experienced candidates do:
- Know your thesis inside out. Read it end-to-end at least once more in the final month. Mark up gaps, inconsistencies, or claims you might struggle to defend. Understand the flow, the evidence, and the implications.
- Prepare your 3–5 minute summary. The opening question is almost always "Tell us briefly about your thesis" or "Walk us through the key chapters." You need a crisp, one-breath version that hits your research question, methods, major findings, and contribution. Practice it aloud; time yourself.
- Do a mock viva. Find 2–3 people in or outside your field who have not read your full thesis and ask them to grill you for 1–2 hours. Use questions from your examiners' published work or general PhD viva question banks. The point is to practice thinking on your feet and identifying weak spots in your argument.
- Reread your examiners' work. Look at their recent publications, especially if they work on overlap topics. Know their argumentative style. Examiners often probe the relation between your work and theirs, sometimes asking "How does your finding compare to the model I published in 20XX?"
- Prepare for methodological scrutiny. Examiners always ask: Why did you use this method? What are its limitations? Did you consider alternatives? You must be ready to justify technical choices, sample sizes, statistical decisions, etc.
- Anticipate the weakness question. One examiner will likely ask, "What do you see as the main limitations of your work?" or "If you were to start over, what would you do differently?" Having a thoughtful, honest answer ready is crucial and shows maturity.
Your graduate school or doctoral college will publish specific guidance on viva procedure, the questions your examiners might raise, and the time allowed for resubmission after minor corrections. Read it carefully—regulations differ between institutions and even between programs within the same university.
Common examiner question types
While every viva is unique, examiners tend to cluster their questions into a few recurring themes. Preparing for these categories will cover most ground:
- Contribution and originality. "What is the novel claim in your thesis?" "How does your work advance the field beyond what was known?" "What gap does it fill?" Examiners want to know that you know what you added.
- Methodology and validity. "Why did you choose this method?" "What are the limitations?" "How would you respond to someone who argues this approach is flawed?" "Did you consider triangulation or alternative approaches?" Be ready to defend technical choices in plain language.
- Relation to examiner expertise. If your examiner has published on the same topic, they may ask how your work relates to theirs, whether you agree or disagree with their findings, or what you would add to their model. This is not a gotcha—it is a probe of your critical engagement with the literature.
- Weaknesses and limitations. "What are the blind spots in your analysis?" "What assumptions does your argument rest on?" "What would you have liked to do but couldn't?" Honest, thoughtful answers are respected here; defensive or evasive replies are not.
- Broader implications. "Who is your audience?" "What are the practical or theoretical implications of your findings?" "How does this relate to policy?" "What would you want a practitioner to take away?" Examiners want to see you think beyond the thesis itself.
- The next step. "If you had funding and time, what would you research next?" or "How does this thesis set up your future work?" This shows you see the viva as one milestone, not an ending.
Frequently asked questions
How long does a PhD viva typically last?
Most vivas last between 1.5 and 3 hours. 2 hours is a reasonable average. Some are shorter (just over an hour); others, especially in humanities, can stretch to 3.5 hours. Your institution's regulations will often set an expected range. The clock counts from the moment examiners begin; breaks to use the toilet do not extend the time.
Who is allowed in the room during a viva?
The two examiners and you are always present. In some universities, your supervisor may attend but must remain silent (and cannot ask questions or intervene). In others, supervisors are explicitly excluded. A few programs allow a "supporter" (a peer or counselor) to sit with the candidate if prior arrangements are made. Check your program's exact policy, as this varies widely.
Can you fail a viva voce?
Yes, although outright failure is rare (typically under 2% of vivas in most UK universities). However, "fail" does not always mean you lose the opportunity to get a doctorate. Some programs allow you to resubmit and take a second viva the following year. In other cases, you may be offered a different award (a taught Master's degree) instead. The conditions for recovery depend on your institution's regulations and the severity of the examiners' concerns. Always check your program handbook for what happens after a fail outcome.
What is the most common viva outcome?
Pass with minor corrections is the most commonly reported outcome in UK and Australian universities, according to published guidance from universities including Edinburgh, Manchester, and ANU. However, the exact proportion varies—some departments report it in 70–80% of vivas; others report lower figures. Your own department may differ. Ask your graduate advisor or check if your institution publishes viva outcome data.
Do you need to prepare slides or a presentation for a viva?
Not always. Many UK vivas have no formal presentation component; they are conversation-based from the start. However, some programs expect or permit a short (10–15 minute) overview, and a few require a full presentation. Check your department's viva procedure document. If slides are expected, they should distill your thesis into key findings and arguments, not reproduce every figure from your written work. If you are unsure, ask your supervisor or the graduate coordinator.
Sources
This page distills guidance from the published viva voce procedures of major UK, Irish, Australian, and New Zealand universities. Viva outcome categories, typical durations, and examiner structures reflect standards outlined by:
- University graduate school handbooks and doctoral college regulations (consulted from publicly available policy documents)
- Thesis examination procedures published by Russell Group and research-intensive universities
- Academic writing guides and thesis support resources from university libraries
- Publications on PhD assessment and viva conduct by academic institutions and thesis support organizations
Because degree requirements, viva procedure, and outcome categories differ by institution, program, and country, you must verify all specifics against your own graduate school's handbook. Do not assume the information on this page matches your program's exact rules. Key things to check:
- How many examiners are appointed and who selects them?
- Are presentation slides required, optional, or not used?
- What is the time limit for minor corrections?
- What happens if you fail: can you resubmit?
- Are supervisors or supporters permitted in the room?
Ask your graduate coordinator, departmental handbook, or thesis advisor for your institution's official viva voce procedure.