Have you ever rehearsed a conversation in your head and still felt your heart hammer when the moment arrived? That is the gap a mock viva is built to close.
Most PhD candidates I speak with know mock vivas exist. They have heard the term in passing, maybe in a department email or a supervision meeting where it was mentioned and then quietly dropped. What they do not know is what one looks like from the inside. So they imagine the worst version. A panel of strangers. A trap door. An interrogation.
The reality is far more humane than that. Here is what happens in a mock viva, step by step, and why it matters more than your supervisor probably told you.
What a mock viva really is
A mock viva is a rehearsal of your real viva voce examination. It is run in the same format, with the same kinds of questions, by people standing in for your examiners. The point is not to predict the questions you will be asked on the day. The point is to put your body and mind through a close approximation of the experience so the real thing feels familiar instead of foreign.
It is distinct from a chat with your supervisor about your thesis. Supervisors tend to know your work too well. They skip past the obvious questions because they already know the answers. A mock viva, done properly, treats you as if the examiner has read your thesis once, has opinions, and wants you to defend your choices out loud.
Format: how long, how many people, what shape
Most mock vivas run between ninety minutes and two and a half hours. That is shorter than a real viva, which can stretch past three hours, but long enough that fatigue starts to set in. You will feel that fatigue. It is part of the rehearsal.
You will usually face one or two examiners. In a real viva you have an internal and an external examiner, and a chair. In a mock you might have one stand-in playing both roles, or two people splitting the work. Either is fine. What matters is that they are asking questions you have not pre-scripted answers for.
The format is question-led. There is no presentation at the start. You sit down, the examiner opens with something gentle, and the discussion unfolds from there. It moves through your thesis chapter by chapter, doubling back when something is unclear, pressing harder when something feels thin.
Who plays the examiners
This varies by institution and by how organised your department is.
In some cases your supervisor will arrange for an internal colleague who has not read your work to step in. This is decent practice if the colleague takes the role seriously and reads enough of the thesis to ask sensible questions.
In other cases the department offers nothing. A surprising number of UK PhD candidates finish their thesis without ever doing a structured mock. The institution treats viva prep as a personal responsibility, which is a structural gap, not a failing on your part. If your supervisor has not raised it, it is reasonable to ask.
The third option is to book a mock viva with us. External facilitators have the advantage of knowing nothing about you or your department politics, which is closer to what you will face on the day.
The kinds of questions you will be asked
The opening question is almost always soft. “Tell me about your thesis in a few minutes.” Or “What drew you to this topic?” It is designed to settle you, not to test you. Use it.
From there the examiner will start probing chapter by chapter. They will ask why you made specific methodological choices and what alternatives you considered. They will ask how a particular finding holds up if you change one of its assumptions. They will ask what your contribution to knowledge is, in plain language, in a sentence you can say without notes. That last one catches people out more often than any other.
You can find a longer breakdown in our 28 viva questions examiners ask post, which is worth reading before you sit down for your mock so you know the territory.
What the examiner is looking for
Here is the thing most candidates get wrong. The examiner is not trying to catch you out. They are trying to see how you think on your feet when a sharp question lands.
They want to know whether you understand your own choices well enough to defend them when challenged. They want to see whether you can hold your ground without becoming defensive, and whether you can concede a point without falling apart. None of that requires you to have a perfect answer ready. It requires you to stay in the conversation.
This is the reframe I want you to hold onto. A mock viva is not a performance test. It is a nervous-system rehearsal. Your body cannot tell the difference between a real viva and a convincing rehearsal of one. That is the whole point. You are not practising your answers. You are practising the experience of being questioned.
How a mock viva ends
At the end the examiner steps out of the role and gives you feedback. This part is as valuable as the questioning itself. You will hear what came across clearly and what felt thin. You will hear which answers you over-explained and which you cut short. You will hear whether you lost your composure when a question pushed on a weak point.
Walk away with two or three concrete things to work on. Not twenty. Two or three. Anything more than that and you will not act on any of it.
For a fuller guide on what to do with that feedback, see our companion post on how to prepare for a mock viva and what to ask for in feedback. And if you want to understand what a mock will and will not replicate, our post on mock viva vs real viva: 5 key differences is worth a look. There is also a useful piece on impressing the examiners and how to prepare for your viva that pairs well with both.
The emotional bit nobody tells you about
In my experience, the strangest thing about a mock viva is how real it feels. You know it is a rehearsal. You booked it. You know the person across the table is not your examiner. And yet your hands still go cold. Your mouth still dries out. You still stumble on the question you thought you had nailed.
That is the work doing its job. Your nervous system is laying down the memory it will draw on when the real day comes. The next time you sit in that chair, the room will feel a little less alien. The questions will feel a little less sharp. You will recognise the rhythm.
What would change for you, if walking into your viva felt like walking into a room you had already been in once before?
0 Comments