26 September 2011

Four months without blogs

As you've noticed, I haven't posted in a while.  I've also not been reading blogs.  My unread number of posts is now 462.  Clearly I'm not going to go back and read all 462 posts that I missed.  I will claim that this was an experiment to see what a (nearly) blog-free world is like.

I actually found that I missed both the reading and the writing, so now (especially that I've switch over to public transportation and so have about an hour to kill in transportation time) I'm going to go back to reading while being transported and blogging when I have time.

I figured I'd return to blogging by saying a bit about a recent experience.  Less than a month ago I had the honor of serving on Jurgen Van Gael's Ph.D. examination committee.  Jurgen did an excellent job and, as perhaps expected, passed.  But what I want to talk about is how the UK model (or at least the Cambridge model) is different from the US model.

In the UK, the examination is done by two faculty members, one internal (this was Stephen Clark) and one external (that was me).  It does not involve the advisor/supervisor, though this person can sit in the room without speaking :).  There is no public presentation and the process we followed was basically to go through the dissertation chapter-by-chapter, ask clarification questions, perhaps some things to get Jurgen to think on his toes, and so on.  This took about two hours.

Contrast this to the (prototypical) US model, where a committee consists of 5 people, perhaps one external (either external to CS or to the university, depending on how your institution sets it up), and includes the advisor.  The defense is typically a 45 minute public presentation followed by questions from the committee in a closed-room environment with the student.

Having been involved, now, in both types, I have to say they each have their pros and cons.  I think the lack of a public presentation in the UK model is a bit of a shame, though of course students could decide to do these anyway.  But it's nice to have something official for parents or spouses to come to if they'd like.  However, in the US, the public presentation, plus the larger committee, probably leads to situation that students often joke about that not even their committee reads their dissertation.  You can always fall back on the presentation, much like students skip class reading when they know that the lecture will cover it all.  When it was just me, Stephen and Jurgen, there's really no hiding in the background :).

I also like how in the UK model, you can skip over the easy stuff and really spend time talking with the student about the deep material.  I found myself much more impressed with how well Jurgen knows his stuff after the examination than before, and this is not a feeling I usually get with US students because their defense it typically quite high-level.  And after 45 minutes of a presentation, plus 15 minutes of audience questions, the last thing anyone wants to do is sit around for another two hours examining the details of the defense chapter-by-chapter.

Regarding the issue of having the advisor there or not, I don't have a strong preference.  The one thing I will say is that by having the advisor missing removes the potential for weird politics.  For instance, I have seen one or two defenses in which an advisor tends to answer questions for the student, without the student first attempting an answer.  If I were on these committees, with a relatively senior advisor, it might be politically awkward to ask them not to do this.  Luckily this issue hasn't come up for me, but I could imagine it happening.

Obviously I don't really expect anyone's policies to change, and I'm not even sure that they should, but I like thinking about things that I've grown used to taking for granted.  Plus, after having gone through the UK model, I think I will grill students a bit more during the Q/A time.  And if this means that fewer students ask me to be on their committees, then there's more time to blog :).


Waleed Ammar said...

Thanks for bringing this up, Hal. The European take on PhD degrees is inherently different than in North America in several important ways, but most PhD holders experience only one. As a result, the world is lacking such comparisons which are of great importance to people considering a graduate school (especially applicants from outside North America who tend to be more open to long-distance relocation).

Adam Lopez said...

I've been at both US and UK Universities, and there are definitely important differences in how the PhD is structured. In the case of the defense (viva voce, as it's called in the UK), there's a good deal of institutional variance, though. For instance, in Edinburgh (at least in the informatics department) the official process is similar to Cambridge, but the viva is usually preceded by a public talk, which is more or less directly equivalent to the public portion of the defense in the US. It is also fairly typical (though I don't think required) for students to do a "draft dissertation defense" (DDD) some months in advance, which is done before a 4- or 5-person committee and more closely resembles a US defense. Possibly this is more onerous (I'm advising someone through it from afar right now so I may have a more informed opinion when it's over :), but it does seem to combine the best elements of both processes that you've pointed out here.

Bob Moore said...

The strangest thesis defense I have participated in was in Sweden, where the external examiner ("opponent" in their terminology) is supposed to explain the dissertation to the committee, who are not expected to be experts in the field. The opponent actually has to do more work than the student in the defense! The opponent doesn't get a vote as to whether the student passes, although he/she takes part in the deliberations of the committee. In the old days, I gather that the opponent literally attacked the dissertation, and the student had to defend it, but this is no longer considered polite behavior, or so I was told.

hal said...

@Bob: I think it's actually the same (or quite similar) in the Netherlands (where Jurgen is from originally) because he told me a similar story about how his friends (who are still there) have to do their defenses.

One thing I was sad about is that apparently in Oxford they have to wear somewhat silly (or at least outdated) attire to the viva. I was really hoping to see Jurgen dressed up, but sadly Cambridge did away with that policy.

Laurens van der Maaten said...

In The Netherlands, the defense is mainly a ceremony: the thesis committee (typically three internal and two external members) has to read and approve the thesis beforehand. Once the thesis is approved and you're allowed to do the defense, it is virtually impossible to fail the defense.

The actual defense usually includes a 10-minute presentation, after which the committee asks questions about the thesis that the student needs to answer. The entire defense is public, and takes exactly one hour: after one hour, a bedel enters the room saying 'hora est' ('it is time') and the defense stops right away. Another funny ritual is the presence of two paranymphs. A long time ago, these paranymphs would serve as physical shield in case of heated debates; now, their role is symbolic (a bit comparable to having a best man at a wedding).

Btw... isn't Jurgen from Belgium (Flanders)?

hal said...

Haha yes of course Jurgen is from Belguim. Sigh, sorry Jurgen. I was very tired yesterday and not thinking clearly!

Anonymous said...

@Bob: I heard the same story for Bernard Lang (Inria researcher, now retired) who was invited to be part of a thesis committee in Sweden. It was only during the lunch time, or a bit before, I can't remember, someone asked him how he was feeling about the swedish thesis defense procedure that he discovered he had to defend the thesis himself. His words were "Non, mais ça va pas la tête !" (a very colloquial way of saying "Are you out of your mind?") , he did it at the end but never again :)

@Hal, in France we have the "best" of two world: first there's a presentation (up to 45 mn-1hour) then any questions from the committee (which can be long), they can ask whatever they want from "page 245, you cite XXX and not YYY, how is that so?" to "can you prove the complexity of your algorithm on this chalkboard. Yes, this one, right there. proceed." or "can you test your parser on this (very tricky) sentence?" (and the poor applicant has to make it run right now and of course justify if results don't match the committee member expectations...) and all of this in front of a large public audience (which came for the free cocktail or for science, one cannot be sure). At the end of the official questions come the ritual "is there a doctor in the audience who would like to ask questions?" and then another round...


Jurgen Van Gael said...

Plus, after having gone through the UK model, I think I will grill students a bit more during the Q/A time.
Haha, I already apologize to all future defendees of Hal!