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The Complete Guide to PhD Vivas


  • A viva involves defending your thesis in an interview-style examination with at least two examiners.
  • The purpose of a viva is to defend your thesis and to demonstrate an in-depth understanding of your research project.
  • They typically last at least two hours, however, there is no formal duration.
  • There are four main outcomes of a viva:
    (1) pass with no corrections (2) pass subject to corrections, (3) fail but be awarded an MPhil, (4) fail and not be awarded anything.

The most common outcome is number 2 – for a student to be asked to amend and re-submit their thesis before it can be accepted as a complete pass.

What is a PhD Viva?

A viva voce, most commonly referred to as just a ‘viva‘, is an interview-style examination conducted at the end of your PhD and is essentially the final hurdle of obtaining the degree. It is the period in which a PhD student’s knowledge and respective work is assessed in detail by independent examiners.

In order to assess the student and their work, the viva sets out to determine:

  • you understand the ideas and theories you have proposed,
  • you can answer questions on elements of your work that the examiners may not be satisfied with,
  • you understand the wider field of research around your subject area, and how your work contributes to this,
  • you aware of the limitations of your work and understand how your work can be developed further.
  • the work you have done is your own and has not been plagiarised,

Note: A viva is a mandatory process required for all PhDs. The exception to this is where a PhD is being obtained through publication as opposed to through the more traditional route of studying.

Who Will Attend a Viva?

All vivas are required to be attended by a minimum of two examiners. Although this theoretically means you could have more than two examiners, the vast majority of vivas keep to two only to maintain the flow of the interview examination.

Of the two examiners, one will be internal, i.e. a member of your university and the other will be external, i.e. a member of a different university. Regardless of whether they are the internal or the external examiner, both examiners will be knowledgeable in your PhD’s area of research and would have read your thesis in detail prior to the viva process.

Besides your two examiners, two other individuals may be present. The first is a chairperson. A chairperson is an individual responsible for monitoring the viva interview and ensuring proper conduct is followed by both the student and examiners at all times. The need for a chairperson is decided by the university you belong to and varies from university to university. The second is your supervisor. The attendance of your supervisor is decided by you, however, your examiners will have the ultimate decision on whether or not they can attend. If present, your supervisor is not allowed to ask questions or affect the outcome of the viva.

To ensure there are no misunderstandings, we’ve summarised this in a table for you:

IndividualMandatory or Optional?Presence decided by?Can Ask Questions and Impacts Outcome?
ExaminersMandatory and minimum of 2Your supervisorYes
ChairpersonOptionalYour universityNo
Your SupervisorOptionalYou, in agreement of both examinersNo

How Long Does a Viva Last?

As all universities have different guidelines and as all PhDs are unique, there are no set durations, however, on average, vivas are at least two hours long.

Your examiners will also influence the duration of your viva as some will favour lengthy discussion, whilst others may not. Typically, your university will consult with your examiners ahead of time and notify you of the likely duration closer to the day of your viva.

What Happens During a Viva?

Regardless of the subject, all PhD vivas will more or less follow the same format as described below.


You will first introduce yourselves to each other, with the internal examiner usually introducing the external examiner. If a chairperson is present, they too will introduce themselves, however, if no chairperson is present, one of the examiners should announce themselves as the ‘chair’. This is because a ‘chair’ needs to be appointed so someone can take an overall lead of the discussion. In the absence of a chairperson, this will typically be the internal examiner.

Procedure Explained

After introductions, the appointed chair will explain the process and procedures of the Viva. All involved parties should already be aware of this, however, it will be reiterated just to ensure the viva stays on track through the upcoming discussion.

Warm-up Questions

Following this, the examiners will then start the questioning process. This will usually start with a few warm-up questions, such as asking you to summarise your thesis and asking what motivated you to undertake the research project.

In-depth Questions

The questions will then naturally increase in difficulty as the examiners progress further into the details of your thesis. This may include questions such as “What was the critical decision you made when determining your research methodology” and “How do your findings impact existing theories or literature?”. As well as being asked open-ended questions, they will also ask you specific questions regarding the methodology, results and analysis underpinning your thesis.

Closing the Viva

Once the examiners have satisfied themselves that they have adequately assessed your knowledge and appraised your thesis, they will draw the viva to a close. This will involve giving you the opportunity to ask questions before the chair officially end the examinations.

What Happens after the Viva?

Once your PhD viva has officially ended, your examiners will ask you to leave the room so they can discuss your performance. Once they have come to a mutual agreement, which may take anywhere from 10 minutes to an hour, they will invite you back inside the room. They will then notify you of your performance and issue you with one of the six following provisional recommendations:

  1. Immediate award of degree: Congratulations, you are one of the very few people who have completely satisfied your examiners the first time around. You are not required to do anything further at this point.
  2. Minor amendments required: The most common recommendation – you will receive a pass on the condition that you make some minor amendments to your thesis and resubmit it to the examiners. The time you have to amend your thesis depends on the number of amendments required. However, it typically ranges from a few days to six months.
  3. Major amendments required: Another common recommendation is that you make major amendments to your thesis, typically carrying out further research and rewriting entire sections before resubmitting to the examiners. Upon acceptance of your amended thesis, you will be awarded your degree.
  4. Immediate award of MPhil: A less common recommendation is that your examiners believe your thesis does not meet the standard for a Doctoral degree but are willing to award you a lower degree (MPhil).
  5. Amendments required for MPhil: A rare recommendation is that your examiners believe your thesis does not meet the standard for a Doctoral degree. They then recommend that you make amendments to your thesis and resubmit for a lower degree (MPhil).
  6. Immediate fail: A very rare recommendation is an immediate fail. In this scenario, you would not be able to make any amendments or resubmit your thesis.

How Do I Arrange a Viva?

With your input, your supervisor will allocate the examiners for your viva. The viva itself will be arranged by either the examiners or, if allocated, the chairperson. The viva will be arranged at least one to two months after you have submitted your thesis and will be arranged for a date and venue suitable for everyone who will be involved.

What Is the Normal Pass Rate for Vivas?

Although there are no official statistics we can share with you, the pass rate for PhD vivas is a lot higher than you’d expect. This is because supervisors will only put their students forward for the viva process when they believe they are ready for it. As a result, most candidates who sit a viva are already well-versed in their PhD topic before they even start preparing for the examination.

As mentioned previously, the most common outcome of a PhD viva is a pass on the condition that amendments be made to your thesis.

How Do I Prepare for a PhD Viva?

To improve your chances of a successful viva, we have put together a viva checklist with advice from the opening discussion to common questions and answers. You can view our checklist here.

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