what is a defense in phd

• PhD Viva Voces – A Complete Guide
• Doing a PhD
• A PhD viva involves defending your thesis in an oral examination with at least two examiners.
• The aim of a PhD viva is to confirm that the work is your own , that you have a deep understanding of your project and, overall, that you are a competent researcher .
• There are no standard durations, but they usually range from one to three hours, with most lasting approximately two hours .
• There are six outcomes of a PhD viva: (1) pass without corrections (2) pass subject to minor corrections, (3) pass subject to major corrections, (4) downgrade to MPhil with no amendments, (5) downgrade to MPhil subject to amendments, (6) immediate fail.
• Almost all students who sit their viva pass it, with the most common outcome being ‘(2) – pass subject to minor corrections’.

What Is a PhD Viva?

A viva voce , more commonly referred to as ‘viva’, is an oral examination conducted at the end of your PhD and is essentially the final hurdle on the path to a doctorate. It is the period in which a student’s knowledge and work are evaluated by independent examiners.

In order to assess the student and their work around their research question, a viva sets out to determine:

• you understand the ideas and theories that you have put forward,
• you can answer questions about elements of your work that the examiners have questions about,
• you understand the broader research in your field and how your work contributes to this,
• you are aware of the limitations of your work and understand how it can be developed further,
• your work makes an original contribution, is your own and has not been plagiarised.

Note: A viva is a compulsory procedure for all PhD students, with the only exception being when a PhD is obtained through publication as opposed to the conventional route of study.

Who Will Attend a Viva?

In the UK, at least two examiners must take part in all vivas. Although you could have more than two examiners, most will not in an attempt to facilitate a smoother questioning process.

One of the two examiners will be internal, i.e. from your university, and the other will be external, i.e. from another university. Regardless, both will be knowledgeable in your research field and have read your thesis beforehand.

In addition to your two examiners, two other people may be present. The first is a chairperson. This is an individual who will be responsible for monitoring the interview and for ensuring proper conduct is followed at all times. The need for an external chairperson will vary between universities, as one of the examiners can also take on this role. The second is your supervisor, whose attendance is decided upon by you in agreement with your examiners. If your supervisor attends, they are prohibited from asking questions or from influencing the outcome of the viva.

To avoid any misunderstandings, we have summarised the above in a table:

Note: In some countries, such as in the United States, a viva is known as a ‘PhD defense’ and is performed publicly in front of a panel or board of examiners and an open audience. In these situations, the student presents their work in the form of a lecture and then faces questions from the examiners and audience which almost acts as a critical appraisal.

How Long Does a Viva Last?

Since all universities have different guidelines , and since all PhDs are unique, there are no standard durations. Typically, however, the duration ranges from one to three hours, with most lasting approximately two hours.

Your examiners will also influence the duration of your viva as some will favour a lengthy discussion, while others may not. Usually, your university will consult your examiners in advance and notify you of the likely duration closer to the day of your viva.

What Happens During a Viva?

Regardless of the subject area, all PhD vivas follow the same examination process format as below.

Introductions

You will introduce yourselves to each other, with the internal examiner normally introducing the external examiner. If an external chairperson is present, they too are introduced; otherwise, this role will be assumed by one of the examiners.

Procedure Explained

After the introductions, the appointed chair will explain the viva process. Although it should already be known to everyone, it will be repeated to ensure the viva remains on track during the forthcoming discussion.

Warm-Up Questions

The examiners will then begin the questioning process. This usually starts with a few simple opening questions, such as asking you to summarise your PhD thesis and what motivated you to carry out the research project.

In-Depth Questions

The viva questions will then naturally increase in difficulty as the examiners go further into the details of your thesis. These may include questions such as “What was the most critical decision you made when determining your research methodology ?”, “Do your findings agree with the current published work?” and “How do your findings impact existing theories or literature? ”. In addition to asking open-ended questions, they will also ask specific questions about the methodology, results and analysis on which your thesis is based.

Closing the Viva

Once the examiners are satisfied that they have thoroughly evaluated your knowledge and thesis, they will invite you to ask any questions you may have, and then bring the oral examination to a close.

What Happens After the Viva?

Once your viva has officially ended, your examiners will ask you to leave the room so that they can discuss your performance. Once a mutual agreement has been reached, which can take anywhere from 10 minutes to an hour, you will be invited back inside and informed of your outcome.

PhD Viva Outcomes

There are six possible outcomes to a viva:

• Immediate award of degree: A rare recommendation – congratulations, you are one of the few people who completely satisfied your examiners the first time around. You do not have to do anything further at this point.
• Minor amendments required: The most common recommendation – you obtain a pass on the condition that you make a number of minor amendments to your thesis, such as clarifying certain points and correcting grammatical errors. The time you have to make these changes depends on the number of them, but is usually one to six months.
• Major amendments required: A somewhat uncommon recommendation – you are requested to make major amendments to your thesis, ranging from further research to collecting more data or rewriting entire sections. Again, the time you have to complete this will depend on the number of changes required, but will usually be six months to one year. You will be awarded your degree once your amended thesis has been reviewed and accepted.
• Immediate award of MPhil: An uncommon recommendation – your examiners believe your thesis does not meet the standard for a doctoral degree but meets the standard for an MPhil (Master of Philosophy), a lower Master’s degree.
• Amendments required for MPhil: A rare recommendation – your examiners believe your thesis does not meet the standard for a doctoral degree, but with several amendments will meet the standard for an MPhil.
• Immediate fail: A very rare recommendation – you are given an immediate fail without the ability to resubmit and without entitlement to an MPhil.

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What Is the Pass Rate for Vivas?

Based on an  analysis of 26,076 PhD students  who took their viva exam between 2006 and 2017, the PhD viva pass rate in the UK is 96%; of those who passed, about 80% were required to make minor amendments to their thesis. The reason for this high pass rate is that supervisors will only put their students forward for a viva once they confidently 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 exam.

How Do I Arrange a Viva?

Your viva will be arranged either by the examiners or by the chairperson. The viva will be arranged at least one to two months after you have submitted your thesis and will arrange a viva date and venue that is suitable for all participants.

Can I Choose My Examiners?

At most universities, you and your supervisor will choose the internal and external examiners yourselves. This is because the examiners must have extensive knowledge of the thesis topic in order to be able to examine you and, as the author of the thesis in question, who else could better determine who they might be than you and your supervisor. The internal examiner is usually quite easy to find given they will be from your institution, but the external examiner may end up being your second or third preference depending on availability.

Can I Take Notes Into a Viva?

A viva is about testing your competence, not your memory. As such, you are allowed to take notes and other supporting material in with you. However, keep in mind that your examiners will not be overly impressed if you constantly have to refer to your notes to answer each question. Because of this, many students prefer to take an annotated copy of their thesis, with important points already highlighted and key chapters marked with post-it notes.

In addition to an annotated copy of a thesis, some students also take:

• a list of questions they would like to ask the examiners,
• notes that were created during their preparation,
• a list of minor corrections they have already identified from their viva prep work.

How Do I Prepare for a PhD Viva?

There are several ways to prepare for a PhD viva, one of the most effective being a mock viva voce examination . This allows you to familiarise yourself with the type of viva questions you will be asked and identify any weak areas you need to improve. They also give you the opportunity to practise without the pressure, giving you more time to think about your answers which will help to make sure that you know your thesis inside out. However, a mock viva exam is just one of many methods available to you – some of the other viva preparation methods can be found on our “ How to Prepare for a PhD Viva ” page.

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What is PhD Dissertation Defense and How to Prepare for It?

Table of Contents

Defending your written dissertation at an oral examination is a crucial step in the culmination of your doctoral journey. The PhD dissertation defense provides an opportunity to present your research study and its main findings, highlight its significance, and defend your work before a committee of experts.

It not only provides a platform to demonstrate and convince the examining committee of your expertise, but also highlights your ability to engage in scholarly discussions.

In this article, we will discuss the importance of the oral defense in the doctoral journey, the key elements of a successful dissertation defense, and how to effectively present and defend your research study before a committee of experts.

What does a PhD Dissertation Defense entail? 

A PhD dissertation defense typically involves two main components: a presentation by the candidate and a question-and-answer session. The presentation summarizes the research methodology, findings, and conclusions.

Public Defense: If the defense is open to the public, audience members may also have the opportunity to ask questions.

Question-and-Answer Session: Committee members will probe the candidate’s understanding of the research, methodology, and implications of their findings. This session can last from one to two hours, depending on the complexity of the research and the depth of questioning.

Committee Deliberation: Once the presentation and Q&A are complete, the candidate will be asked to leave the room while the committee discusses the dissertation. They will then decide whether to:

• Fail the dissertation (rare)
• Suggest revisions before final approval
• Approve it as is

Committee Composition: The examining committee typically consists of:

• Chair: An external faculty member from another department who oversees the defense process.
• Supervisor: The candidate’s primary advisor.
• Internal Examiners: Faculty members from the candidate’s department or another relevant department.
• External Examiner: A specialist in the subject matter from outside the institution.

Note: The Chair does not review the dissertation or ask questions. Their main role is to ensure a fair and impartial defense.

How to prepare for dissertation defense?

A successful PhD dissertation defense requires careful preparation and effective communication. By understanding the key components of the defense, anticipating questions, and practicing your presentation, you can increase your confidence and deliver a strong performance. This guide will provide you with valuable tips to help you prepare for this important milestone in your academic journey.

Oral Presentation:

• Format and Time: Consult your department for specific guidelines. Presentations typically last 20-30 minutes.
• Focus: Highlight the most significant contributions and conclusions of your research.
• Visual Aids: Use PowerPoint or other software to create slides.
• Outline: Refer to your thesis’s introductory chapter for a potential structure.

Anticipating Questions:

• Common Themes: Consider questions related to your conceptual framework, research design, sampling, hypothesis formulation, and the study’s contribution to existing knowledge.
• Personalized Questions: As you read your thesis, identify potential questions the committee might ask based on its specific content.

Tips for a Successful PhD Dissertation Defense

A successful PhD dissertation defense requires careful preparation and effective communication. Here are some key tips to help you prepare:

Before the Defense:

• Thorough Review: Read your thesis carefully to anticipate questions.
• Observe Others: Attend defenses of other candidates to understand the process.
• Seek Guidance: Talk to successful PhD candidates and your supervisor for advice.
• Practice Responses: Prepare for potential questions and practice your answers.
• Rehearse Presentation: Practice delivering your presentation aloud to improve clarity and refine points.

During the Defense:

• Stay Calm: Manage your nerves and maintain confidence.
• Listen Carefully: Fully understand the committee’s questions before responding.
• Be Clear and Concise: Answer questions directly and avoid rambling.
• Ask for Clarification: If a question is unclear, don’t hesitate to ask for clarification.

After the Defense:

• Address Revisions: If requested, work with your supervisor to address any necessary revisions promptly.

Remember: Preparation is key. By following these guidelines and practicing effectively, you can increase your confidence and deliver a successful defense.

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