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A PhD viva voce is an oral examination at the very end of a doctoral programme. In simple terms, it is the stage where a PhD candidate must defend their thesis. This defence takes place in front of one or more examiners. The candidate answers questions about their research so the examiners can probe their understanding.
The Latin term “viva voce” literally means “with the living voice.” This highlights that it is a spoken examination rather than a written one (Brähler, 2014).
The viva is not just a formality – it serves a critical purpose in the doctoral assessment. It allows examiners to verify several crucial points about the work. For instance, they check that the work is genuinely the candidate’s own and that the research is original. They also confirm that the candidate has a deep understanding of their field and methods (UKCGE, n.d.).
In other words, the viva ensures that the new doctorate holder is capable of conducting independent research at a high level. It also gives the candidate an opportunity to clarify any issues in the thesis and discuss their work in depth. The process can be intellectually challenging, but it is also a chance to showcase your expertise. Most students who reach this stage do pass the viva. However, examiners commonly require some corrections to the thesis afterwards (Bennett, n.d.; DiscoverPhDs, n.d.).
The viva voce remains a cornerstone of doctoral assessment in many education systems. It provides a final checkpoint before the university confers the PhD degree.
Why is it called ‘viva voce’?
The term viva voce is a Latin phrase meaning “by live voice” or “with living voice,” which directly refers to the oral nature of the examination. Universities have long used oral exams to test understanding, and the PhD viva is a continuation of that tradition. In everyday usage, academics often shorten the term to simply “viva.” When someone asks “what is a PhD viva?” they mean this spoken defence of the doctoral thesis.
In essence, viva voce underscores that the candidate must answer questions and explain their work face-to-face with the examiners, rather than through written responses. This distinguishes the viva from the thesis document itself (and from written exams).
The phrase “viva voce” is widely used in the UK and some other countries. By contrast, in the United States the same kind of examination is usually called a doctoral “defense” (or defence in British spelling). However, both terms refer to the same concept: an oral test in which PhD candidates defend their work using their voice.
Different approaches to the PhD viva around the world
Despite its common purpose, countries around the world conduct the PhD final oral exam in different ways. The format of a viva voce (or defence) can vary significantly by country, which can sometimes cause confusion for students. Below we outline a few key differences among the UK, US and European systems.
The UK viva voce examination
In the United Kingdom, the PhD viva is typically a closed-door examination. It is usually just the candidate and two examiners in the room. One examiner is internal to the university and the other is external (from another institution). There is no audience or public attendance in a standard UK viva. In fact, the PhD supervisor normally does not attend the viva either (Cambridge University, 2023).
This private setting allows for an intensive, frank discussion of the research between the candidate and the examiners. The examiners will ask a wide range of questions. They often start with simple clarifications about methods or data, then probe deeper into the findings and their implications.
A UK viva can last from about one to three hours. It is known to be a rigorous academic dialogue rather than a perfunctory presentation.
Importantly, the UK viva is not just a formality. The examiners’ decision depends not only on the quality of the written thesis but also on how well the candidate defends their work (Brähler, 2014). That said, outright failure at the viva stage is very rare. Typically, by the time the thesis is submitted and the viva is scheduled, the supervisor is confident that the work is ready. In most cases, the viva serves mainly to confirm the candidate’s competence and the originality of their research. It takes place in a focused setting free from distractions.
The US dissertation defense
In the United States, the final oral examination is usually called a dissertation “defense” (using the American spelling) rather than a viva voce. The format and atmosphere of a US defense differ from those of a UK viva.
First, a US defense is often a public event. Many doctoral programs require the candidate to present their research in an open seminar. This presentation is typically open to faculty, students and sometimes family or friends. There may also be a brief open question session for the attendees.
After the public presentation, there is usually a closed-door session. In this closed portion of the defense, the candidate’s dissertation committee examines them in detail on the work.
The committee in the US is usually composed of several faculty members who have supervised or advised the student’s research. Often the main supervisor serves as the chair of the committee. This means the examiners are familiar faces who have already played a part in the project (Zwaan, 2013).
The questioning can still be rigorous and challenging. However, the tone is often more collegial – more of a scholarly discussion than an interrogation. The presence of the supervisor as an examiner is a major difference from the UK system. In the UK, the supervisor is not on the examining panel.
Another difference is in how the outcome is decided. In the US, the committee typically deliberates together and often takes a vote to determine whether to approve the dissertation. Because this committee has worked closely with the student, any serious issues with the research are usually resolved before the defense takes place. As a result, outright failure at the defense stage is very uncommon (much like in the UK). However, the committee may still require the candidate to make some revisions to the dissertation text before final approval is granted.
Overall, the US dissertation defense is both an examination and a symbolic milestone. It lacks the formal pomp of some European ceremonies. Still, it marks the candidate’s transition from student to peer in the academic community.
European public defences
Many countries in Europe have their own traditions for the PhD defence, often involving a public ceremony. For example, in the Netherlands the PhD defence is a highly formal event (van Bakel, 2013). Well before the day of the defence, a committee of experts must approve the written thesis. The defence itself then serves as a final confirmation of the candidate’s achievement – and a celebration of it.
A Dutch PhD defence usually takes place in an ornate hall with the candidate’s family, friends and colleagues present. The candidate may even have two paranymphs (support assistants) standing by their side. This tradition dates back to medieval times, when paranymphs could help defend the candidate – even physically, if debates got heated. Today, the paranymphs are purely symbolic supporters who assist the candidate and handle practicalities.
The examining committee in the Netherlands is large – often around six to eight members. It includes the candidate’s supervisor (called the promotor), other professors from the university, and some external experts. The committee members wear full academic regalia. Each examiner (sometimes called an “opponent”) has a fixed time slot to pose questions to the candidate in turn.
The PhD defence has a strict time limit. In the Netherlands, the ceremony typically lasts exactly 45 or 60 minutes. At the appointed moment, a university beadle (ceremonial officer) enters and declares “Hora est” – Latin for “the hour has come.” Often the beadle emphasises this by striking a ceremonial mace on the floor. This immediately ends the questioning – even if someone is mid-sentence (van Bakel, 2013).
After the questioning period, the committee withdraws briefly to confer. However, since the thesis was already approved in advance, the outcome is almost always positive. The candidate then formally receives the doctorate in a brief ceremony, often including a laudatory speech by the supervisor. A reception or celebration for the new doctor usually follows.
Other European countries have variations on the public defence. Some have the public event without as much ceremony. Others (for example, in Germany or France) combine a closed examination with a public colloquium. The common thread is that these defences emphasise a public demonstration of the new doctor’s scholarship. Despite the different cultural rituals, the essential goal remains the same. The candidate must answer questions about their research and demonstrate their expertise.
Note: Within a given country, viva formats tend to be similar across academic disciplines. There may be minor differences between disciplines. For example, a practice-based arts PhD might include an exhibition or creative portfolio as part of the project, which could be discussed during the viva. However, the core requirement – orally defending the research – does not change.
Who attends the viva and what are their roles?
A PhD viva voce typically involves several key participants, each with a defined role. Understanding who is in the room and why they are there can help demystify the process:
PhD candidate:
This is the doctoral student who is defending their thesis. The candidate’s role is to answer questions, explain and justify their research decisions, and demonstrate their knowledge. They should be prepared to discuss any aspect of their thesis and the broader context of their field.
Internal examiner:
One examiner is usually an academic from the candidate’s own university (UKCGE, n.d.). This internal examiner evaluates the work and ensures the examination follows the university’s regulations. They are knowledgeable in the field and help make sure the candidate is treated fairly according to local standards.
External examiner:
An external examiner comes from outside the candidate’s university. Usually this person is an expert in the thesis topic but has had no prior involvement in the project. The external’s role is to provide an independent, unbiased assessment of the work (Bennett, n.d.), helping to maintain high academic standards. In many systems (e.g. the UK) an external examiner is mandatory to ensure impartiality.
Independent chair:
Some universities appoint an independent chairperson to oversee the viva (examples: University of Cambridge, Portsmouth, Birbeck, Loughborough, Essex, Wolverhampton, Bristol and many more). The chair is not an examiner and does not question the candidate on the content. Instead, they ensure the examination follows proper procedure (for example, keeping time and handling any issues).
Not every viva has a chair; this depends on the university’s policy. A chair is more likely to be appointed if needed to ensure fairness (for instance, if the examiners are very new or all external). The chair does not influence the outcome.
Supervisor:
The role of the PhD supervisor (primary advisor) in the viva varies by country.
- In the UK, the supervisor usually does not attend the viva (or may attend only as a silent observer), so that the candidate speaks for themselves (UKCGE, n.d.).
- In the US the supervisor typically is a member of the examining committee and actively participates in questioning.
- In some European countries, the supervisor might attend the defence ceremony and perhaps introduce the work, but generally does not interrogate the candidate.
If a supervisor is present at a viva, they must remain neutral and cannot answer questions on the student’s behalf.
Additional examiners/opponents:
Many vivas include additional committee members or opponents beyond the primary internal and external examiners. For example, in the US the PhD committee often includes several faculty members from the department, and sometimes an outside specialist.
In a European public defence, there may be a panel of opponents who each question the candidate (van Bakel, 2013). These individuals all serve as examiners, collectively evaluating the work and the candidate’s understanding.
Audience (for public defences):
In countries such as the US, the initial part of the PhD defence is often public. During this stage, an audience of students, academics, friends, and family can observe the candidate’s presentation. However, the formal examination by the committee happens privately.
In other countries, notably the Netherlands, the whole defence is a public ceremony, though only the appointed examiners can question the candidate. The audience’s presence in these settings provides transparency and serves to publicly celebrate the candidate’s scholarly achievement.
In contrast, the UK viva is typically private, with no audience permitted.
All the participants ultimately share a common purpose: to uphold high academic standards while giving the candidate the opportunity to succeed. In fact, experienced examiners usually want a worthy candidate to pass. They will give the candidate every reasonable chance to do so (Mullins and Kiley, 2002).
Possible outcomes of a PhD viva
The PhD failure rate in the UK is 19.5%, with 16.2% of students leaving their PhD programme early, and 3.3% of students failing their viva. 80.5% of all students who enrol onto a PhD programme successfully complete it and are awarded a doctorate.
After the questioning is over, the examiners deliberate privately and decide on the outcome of the examination. The exact categories of outcomes can differ slightly by university, but generally the possible outcomes of a PhD viva fall into a common set:
Pass with no corrections: The thesis is accepted as it stands, or with only very trivial edits. This outcome is relatively uncommon on a first viva, but it does happen. If you receive a pass with no corrections, it means the examiners found essentially nothing that needs changing – an excellent result.
Pass with minor corrections: This is the most common outcome. The thesis is fundamentally sound and the defence was satisfactory, but the examiners have noted some minor issues to be addressed (e.g. small editorial changes, clarifications or missing references). The candidate is usually given a short timeframe (typically 1–3 months) to make these corrections. Once the internal examiner (or other designated examiner) approves the revised thesis, the university then awards the PhD.
Pass with major corrections: The candidate will pass, but only after significant changes are made to the thesis. “Major corrections” might involve rewriting certain chapters, re-analysing some data or adding substantial new content. A longer period (often 6–12 months) is allowed for these revisions. A second viva is usually not required in this case – the examiners will review the corrected thesis and, if it now meets the standard, the PhD is then conferred.
Revise and resubmit: This outcome is less common. It means the thesis in its current form does not meet the PhD standard, but could reach that standard with extensive further work. The examiners allow the candidate to substantially rework the thesis and then resubmit it, typically within a year or more. The resubmitted thesis will be re-examined – usually including another viva voce examination. This is effectively a second chance to pass once major improvements have been made.
Award of lower degree (MPhil): In some cases, the work may be judged not to be PhD-quality but sufficient for a lower research degree such as a Master of Philosophy. The examiners can recommend that the candidate receive an MPhil degree instead of a PhD. This might be conditional on some amendments to the thesis or offered outright. The candidate may be given the choice to accept the MPhil or to try to revise and resubmit for a PhD later. Such outcomes are rare, and are only considered when the gap between the thesis and doctoral standard is too large to bridge in a reasonable time.
Fail (no degree awarded): This is the most severe outcome and is extremely rare. It means the thesis and defence did not meet the required standard, and the candidate cannot resubmit. A fail usually only occurs if there are fundamental, unfixable flaws in the work or evidence of academic misconduct (e.g. plagiarism). In practice, universities have processes to avoid a candidate reaching a viva if outright failure is the likely result. As noted above, the vast majority of candidates who make it to the viva will ultimately pass in some form (DiscoverPhDs, n.d.).
References and further reading:
- Bennett, M. (n.d.) What is the PhD Viva? FindAPhD [Online]. Available at: https://www.findaphd.com/guides/phd-viva-exam (Accessed: 1 Dec 2025).
- Brähler, V. (2014) Defending your PhD thesis in… the United Kingdom. Researching Security Network, September 2014. Available at: https://researchingsecurity.org/experiences/phd-thesis-defence/defending-your-phd-thesis-in-the-united-kingdom/ (Accessed: 1 Dec 2025).
- Cambridge University (2023) The oral examination (viva). Cambridge Students – Examination Guidance [Online]. Available at: https://www.cambridgestudents.cam.ac.uk/exams/students/postgraduate-exam-information/writing-submitting-and-examination/phd-edd-msc-mlitt/oral-examination (Accessed: 1 Dec 2025).
- DiscoverPhDs (n.d.) PhD Viva Voces – A Complete Guide. DiscoverPhDs [Online]. Available at: https://www.discoverphds.com/advice/doing/vivas (Accessed: 1 Dec 2025).
- UK Council for Graduate Education (UKCGE) (n.d.) Guidance on Preparing for your Viva. UKCGE [Online]. Available at: https://ukcge.ac.uk/assets/resources/Preparing-for-your-Viva-UK-Council-for-Graduate-Education.pdf (Accessed: 1 Dec 2025).
- van Bakel, M. (2013) ‘Defending your PhD thesis: the Dutch way’, Marian van Bakel Blog, 27 February 2013. Available at: https://marianvanbakel.wordpress.com/2013/02/27/defending-your-phd-thesis-the-dutch-way/ (Accessed: 1 Dec 2025).
- Zwaan, R.A. (2013) ‘Let the Sabers Rattle: A Cross-cultural Comparison of Doctoral Defenses’, Drang naar Samenhang (blog), 15 July 2013. Available at: https://rolfzwaan.blogspot.com/2013/07/let-sabers-rattle-cross-cultural.html (Accessed: 1 Dec 2025).
- Mullins, G. and Kiley, M. (2002) ‘“It’s a PhD, not a Nobel Prize”: how experienced examiners assess research theses’, Studies in Higher Education, 27(4), pp. 369–386.