PhD viva, UK style

Having recently, happily, had several PhD students completing in short order, I’ve been approaching external PhD examiners. Occasionally I find myself asking someone who’s not done any / many in the UK previously. As our system – as all such systems! – is a bit different to those in other parts of the world, I’ve written a few notes on a couple of occasions about what to expect. So I figured I might as well publish them.

What follows is my impression / understanding based on experience here in the Department of Computer Science & Technology, Cambridge University ca. 2025. Your Mileage May Vary anywhen and anywhere else, including anywhere else in the UK – check local regulations to be sure.

In terms of process, the system here is that candidates submit their complete dissertation and then undergo a “viva voce” (oral examination). It would be usual for the viva to take place within 2—3 months of submission. It’s better (IMO, much better) if it can happen in person but we may still be able to arrange to do it online in extremis.

There are two examiners:

1. The internal examiner (typically connected to the Department) who ensures the process is followed properly but may not be a deep expert in the specific topic, and
2. The external examiner (from outside the University) who is there as the subject matter expert.

The viva consists of the two examiners asking the candidate questions about their dissertation until they’re satisfied; typically this takes at least 2h and can go longer, though more than 3.5—4h is unusual in my experience.

The examiners are each expected to read the dissertation in detail before the viva and each write a short (typically 1—2pp) independent report giving their opinion, outlining any concerns they will have and the resulting topics/questions they will be exploring in the viva, and indicating what their a priori judgement is in terms of recommendation (roughly: pass/pass with corrections/revise & resubmit/no Ph.D. but you can have a Masters/fail).

The examiners will then typically meet ~30min or so before the viva to discuss their independent reports and decide on the approach to take in the viva. After the viva they write a joint report (usually shorter than their independent reports; perhaps 0.5pp) outlining what happened in the viva, as well as making a final recommendation and providing (if appropriate) a list of corrections that must be satisfied for the candidate to pass.

Finally, the University pays a (risibly small) honorarium to the external examiner for doing the viva plus reasonable expenses.