I know that you are likely to suggest "Ask your supervisor. He/She will know best.".

While that is obviously true, I would like to know from your personal experience either as the PhD candidate or as the examiner: What should I expect in my viva?

For example:

  • Should I expect to be asked about the history of my topic?
  • About the research cited in my thesis (i.e references - will they ask me about them? I have over 100...)?
  • About methods used?
  • About justifications for my conclusions?
  • etc

What should one expect, in general, to be asked? I am PhD student in the UK.


3 Answers 3


There is one critical question that is asked in every Phd viva, be it either directly or indirectly, that is "what is the original contribution of your thesis to knowledge". To be awarded a Phd the result of the research must be to contribute something new to the planetary or disciplines store of knowledge. You must have done something new and know what that thing is.

It is the very purpose of a viva to discover if you know that. Saying "I do not know" to this question can result in a Phd failure.

Other questions will seek to discover if you really understand the works you are citing in your bibliography; have you actually read and understood them and do you know how they relate to your work.

The third aspect of a viva is to resolve any ambiguity that the examiners read into your writing. Which of the possible interpretations of the words and conclusions did you actually mean. You might not have realised that your thesis contained ambiguity but the examiners will certainly find it. They will also seek to expand on or explore elements that are not clearly explained and get you to clarify them.

The answers to all these questions will determine if you have to make corrections to the thesis to resolve these ambiguities or make clarification, or even conduct more research to resolve those matters.

This is written from the perspective of a Phd examiner, both internal and external and experience as an independent chair of such vivas.


I recently (2-3 months ago) passed my PhD viva in Computer Science at a UK institution in the top 100. I will relay the useful points from my viva experience, but I preface this by saying that yours may differ. Ultimately the viva is a product of the examiners, and different examiners have different priorities. To reply to your questions point by point:

  • I was not asked about the history of the topic at all.
  • I was not asked to discuss any particular reference in detail.
  • We did have some very in depth conversation about methods used (specifically my use of Principal Components Analysis), but in a visual sense, not in the sense of having to recall the formulae. This demonstrated that I knew why I was using it, how it applied to my problem and what the novelty of my approach was.
  • Some of my stated conclusions were not specific enough. This was brought up and narrowing their scope was part of minor corrections.

Whether those are of any use to you is unclear. However, the best pieces of advice I received in hindsight were:

  • Focus on what you wrote, not excruciating detail on the methods you used and the papers you cited. Read through the thesis in its entirety, and if there is any written or implied detail that you do not feel 100% confident explaining, then go and revise that. My colleagues tell me that their vivas were all focused on the thesis claims and content, and mine was no exception. Don't lose sight of the big picture of the thesis amid the minutiae.
  • Don't defend the indefensible. If you get caught out on some detail and what you put is wrong, just concede the point, suck it up and move on. It will go into corrections, no big deal. Flogging a dead horse will just make things worse.
  • As a side to the last point, you should still be robust. The examiners may play devil's advocate, and if they pick up on something that you know is right, this is the time to commit to discussing it. Perhaps concede that it could be explained better in the text if you are struggling to conclude the argument.
  • Don't burn yourself out. Assuming of course that you wrote the thesis entirely, a week of good revision before the viva should be plenty to get you through.

I hope these are of some help to you.


What should I expect in my viva?

Every viva is unique, but the first question will likely be standard in your department, ask a fellow student (and post the reply in a comment below).

Regarding your specific questions, you may be asked about each of them:

Should I expect to be asked about the history of my topic?

You may be asked to contextualise your research within the broader field.

About the research cited in my thesis?

You may be asked about any citation. For any particularly closely related citation, you may be asked to explain the differences between your work and the cited works.

About methods used?

You may be asked to explain the methods (to demonstrate that you understand them), to justify the appropriateness of the methods, and to explain alternative methods.

About justifications for my conclusions?

I'm not sure I understand the question, could you clarify in a comment below?

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