PhD viva preparation guide

Common PhD Viva Questions and How to Answer Them

PhD viva questions are rarely random. Most questions test whether you understand your thesis, whether the work is your own, whether your contribution is original, whether your methods are justified, and whether your claims are appropriately bounded.

The University of Cambridge describes the viva as an oral examination that gives you the opportunity to defend your thesis and clarify matters raised by the examiners. It also allows examiners to probe your knowledge in the field, assure themselves that the work is your own, clarify collaboration, and reach a conclusion about the examination outcome. The Quality Assurance Agency for Higher Education states that doctoral graduates demonstrate an original contribution to knowledge through original research or the original application of existing knowledge or understanding.

Core idea: Do not prepare viva questions as memorised scripts. Prepare answer structures. A strong answer usually gives a direct response, explains the evidence, names the trade off, defines the limit, and shows scholarly judgement.

1. Opening questions

Opening questions are usually designed to let you orient the examiners and demonstrate ownership. They are not casual small talk. They test whether you can summarise the thesis clearly before the detailed examination begins.

Common questions:

  • Can you briefly summarise your thesis?
  • What is the central argument of your thesis?
  • How did you come to this research topic?
  • What should we know before discussing the chapters in detail?

How to answer: Use problem, gap, method, finding, contribution. Avoid beginning with a long personal history. Start with the intellectual problem.

Example answer: My thesis examines how X occurs in Y setting. Previous research has mainly explained A, but it has not fully addressed B. I studied this through C method and D data. The main finding is E, and the contribution is a more precise account of F.

2. Contribution and originality questions

Contribution questions are central because the doctorate requires an original contribution to knowledge. The examiner is not asking you to claim that your thesis changes the whole discipline. They are asking you to identify exactly what your work adds.

Common questions:

  • What is the original contribution of your thesis?
  • What is new compared with existing work?
  • Which chapter best demonstrates originality?
  • What is the most important contribution?
  • How does your thesis change how we understand the problem?

How to answer: State the contribution type, locate it against prior work, then point to evidence in the thesis.

Example answer: The thesis makes an empirical and methodological contribution. Empirically, it provides evidence on X in a setting that has not been systematically studied. Methodologically, it develops a protocol for comparing Y. The evidence appears in chapters three and four, where I present the dataset, coding process, and evaluation results.

3. Literature and field positioning questions

Literature questions test whether you understand the field around your thesis. You do not need to recite every paper. You need to explain the debate, the gap, the strongest opposing view, and how your thesis sits in relation to existing work.

Common questions:

  • Which literature most influenced your thesis?
  • Where does your thesis sit in the field?
  • Who would disagree with your argument?
  • What has changed in the literature since you submitted?
  • Why did you focus on this body of work rather than another?

How to answer: Divide the literature into two or three streams. For each stream, say what it explains, what it leaves open, and how your thesis responds.

Example answer: The first stream explains X, but it does not account for Y. The second stream provides methods for Z, but it has rarely been applied to this setting. My thesis connects these streams by showing how X and Z interact in Y context.

4. Research design and methodology questions

Methodology questions test whether your design fits your research question. A weak answer says that the method was common or convenient. A strong answer explains why the method was appropriate, why alternatives were less suitable, and how you handled validity threats.

Common questions:

  • Why did you choose this methodology?
  • Why did you not use an alternative method?
  • How did your method answer your research question?
  • What are the main threats to validity or reliability?
  • How would your findings change if you used another method?

How to answer: Use question, evidence, method fit, alternative, limitation.

Example answer: I chose this method because the research question required detailed evidence about decision making rather than only outcome frequency. A survey would have given broader coverage, but it would not have captured the reasoning process. The main limitation is sample size, so I treat the findings as bounded explanatory evidence rather than universal generalisation.

5. Data, sample, and evidence questions

Examiners often test whether your evidence can support your claims. They may ask about sample size, case selection, dataset quality, measurement validity, coding procedures, missing data, or representativeness.

Common questions:

  • Why is this sample appropriate?
  • How did you select the cases?
  • How did you ensure data quality?
  • What evidence is strongest in your thesis?
  • Which evidence is weakest?

How to answer: Explain the selection logic. Then define what kind of claim the evidence supports and what kind of claim it does not support.

Example answer: The sample was selected because these cases directly represent the phenomenon under study. It is not designed to represent every possible context. It supports a bounded claim about how X appears in Y setting, and it provides a basis for future comparative work across broader settings.

6. Findings and interpretation questions

Findings questions test whether you can explain what you found and why it matters. The danger is to describe results without interpretation. Examiners want to know how the findings answer the research question and how they change the field’s understanding.

Common questions:

  • What is your most important finding?
  • Which finding surprised you most?
  • How do the findings answer your research question?
  • What is the relationship between chapter four and chapter five?
  • How confident are you in your interpretation?

How to answer: State the finding, link it to evidence, explain the interpretation, then define the confidence level.

Example answer: The most important finding is that X occurs not because of A alone, but because A interacts with B. The evidence comes from the comparison across cases in chapter five. I am confident about the interaction within this dataset, but I would not claim that the same pattern holds across all contexts without further comparative work.

7. Limitations and weakness questions

Limitation questions are not traps. They test whether you understand the boundary of your claims. A strong candidate does not pretend the thesis is perfect. A strong candidate explains what the limitation means and why the contribution still holds.

Common questions:

  • What is the main weakness of your thesis?
  • What would you do differently if you started again?
  • Does this limitation undermine your contribution?
  • What are the strongest counterarguments to your conclusion?
  • Which chapter is the weakest?

How to answer: Name the limitation, define its effect, explain how you managed it, and state what remains valid.

Example answer: The main limitation is that the empirical setting is narrow. This limits generalisability, but it does not undermine the central contribution because the thesis makes a bounded claim about this class of cases. I managed the limitation through transparent case selection, detailed analysis, and careful wording of the conclusions.

8. Ownership and collaboration questions

The viva tests whether the work is yours. This is especially important if your thesis includes co authored papers, shared datasets, joint experiments, supervisor led projects, or team based infrastructure.

Common questions:

  • Which parts of the work are specifically yours?
  • How did your collaborators contribute?
  • Who designed the study?
  • Who collected and analysed the data?
  • How independent was your contribution?

How to answer: Be precise. Separate idea, design, data, implementation, analysis, writing, and interpretation.

Example answer: I designed the research questions, built the analysis framework, implemented the evaluation scripts, conducted the main analysis, and wrote the interpretation. The collaboration provided access to the dataset and feedback on domain assumptions, but the analytical contribution and thesis argument are mine.

9. Ethics and integrity questions

Ethics questions test whether you can account for your responsibilities as a researcher. Depending on the discipline, this may involve consent, confidentiality, data protection, risk to participants, positionality, reproducibility, research integrity, or dual use concerns.

Common questions:

  • What were the main ethical issues in your research?
  • How did you protect participants or data subjects?
  • How did you handle confidentiality?
  • Could your method or tool be misused?
  • How reproducible is your work?

How to answer: Explain the ethical issue, the procedure you used, the remaining risk, and the reason the approach was proportionate.

Example answer: The main ethical issue was handling sensitive participant data. I addressed this through informed consent, anonymisation, restricted storage, and reporting findings at a level that avoided identification. The remaining risk is that some contextual details could still be recognisable, so I removed or generalised those details in the final thesis.

10. Corrections and improvement questions

Examiners may ask how you would improve the thesis. This does not necessarily mean the viva is going badly. It is a way to test judgement. Answer by separating corrections, improvements, and new research.

Common questions:

  • What corrections do you already know are needed?
  • Which section would you rewrite?
  • What would improve the thesis most?
  • What would be beyond the scope of this thesis?
  • How would you respond to this criticism?

How to answer: Acknowledge the issue, specify the revision, and avoid expanding the thesis into a new project.

Example answer: I would revise the discussion section to make the boundary of the claim clearer. I would not add a new empirical study at this stage because that would be a new research project. The correction I would make is to define the scope more explicitly and connect the limitation to future work.

11. Future work and publication questions

Future work questions test whether you understand the research trajectory opened by the thesis. Avoid giving an unfocused list. Explain what follows logically from the contribution.

Common questions:

  • What future research follows from your thesis?
  • What would you publish first?
  • How would you extend the study?
  • What would you do with more time or funding?
  • What is the next major question in this field?

How to answer: Connect future work to the thesis limitations and contribution. Do not make it sound as if the current thesis is unfinished.

Example answer: The next step is not to redo the thesis, but to extend its scope. The thesis establishes the framework in one setting. Future work should test the framework across additional contexts, compare its performance against alternative methods, and examine whether practitioners can use it in real workflows.

12. How to answer when you do not know

You may receive a question you cannot answer fully. The goal is not to pretend. The goal is to remain intellectually controlled. A good answer separates what you know, what you can infer, and what would need further investigation.

Weak answer: I am not sure. I did not look at that.

Stronger answer: I did not examine that directly in the thesis, so I would not want to overstate the answer. Based on the evidence in chapter five, I would expect X, but testing that properly would require Y data and Z method. I would therefore treat it as a future research question rather than a conclusion of this thesis.

13. A general viva answer structure

Most viva answers can use the same underlying structure. First, answer the question directly. Second, point to evidence. Third, explain the reasoning. Fourth, acknowledge the limitation. Fifth, return to the contribution.

Answer structure:

  • Direct answer: give the examiner a clear first sentence.
  • Evidence: point to chapter, data, method, result, or literature.
  • Reasoning: explain why the evidence supports the claim.
  • Boundary: define what the claim does not cover.
  • Contribution: connect the answer back to what the thesis adds.

14. Final PhD viva questions checklist

Before the viva, check whether you can answer these questions aloud without reading from a script:

Practise PhD viva questions with MockBase

Reading common questions is useful, but the viva tests whether you can answer aloud under pressure. Use MockBase to practise realistic viva questions on contribution, literature, methodology, findings, limitations, ownership, corrections, and future work.

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Related guides

How to prepare for a PhD viva How to defend your thesis contribution How to prepare for a faculty interview How to prepare a research vision for an academic interview How to answer academic job interview questions

Preparation sources

This guide was informed by official doctoral standards and viva guidance from QAA, Cambridge, UCL, Edinburgh, UKCGE, and the Scottish Graduate School of Social Science.