Rambles around computer science

Diverting trains of thought, wasting precious time

Sat, 02 May 2009

Doing the mathsssss: supervisions

I just finished my supervising for the year (since I avoid supervising Easter term courses). As with so many things, there seems to be a major difference in how supervising CS is “supposed” to work and how it actually works. The usual rule of thumb is that there should be one contact hour of supervision for every three or four hours of lectures. What's “supposed” to happen is that the students do some self-study on the lectured material, attempt some exercises, hand in their answers, and let the supervisor go over the subset of material which they have revealed, by their attempts, that they didn't manage to understand by self-study. In my first year as an undergraduate, when I studied physics, physics supervisions followed exactly this pattern, and they were usually pleasant and relaxed, with time left over to talk about “interesting” discursive matters.

Unfortunately, during CS supervisions (both when I give them, and when I was the student), what usually happens is that the supervisor seems to go over almost everything in supervision. Why? Surely the students don't get nothing out of self-study? The whole supervising experience is much less pleasant because there's a constant feeling of a need to rush through the material to cover the necessary amount in an hour. Although the official advice that “it's better to cover a few things well than everything poorly” is undoubtedly true, it's hard to put this to the students, who can become anxious and/or somewhat indignant if their supervisor declines to cover a particular topic. So usually I end up rushing, and letting supervisions overrun, neither of which are particularly pleasant.

One problem might be that my students are (as my former self presumably was) lazy and don't put so much effort into self-study. Another is that, in a group of two or three, there's less overlap in what the students “didn't get” by themselves, so the union is close to the full set of course material. Related to this is the problem that, since computer science is mostly about concepts rather than techniques, learning failure modes are “softer” than, say, in physics---it's quite common for students to “almost get it”, but not quite well enough to avoid going over it in the supervision.

The problems I just mentioned are not easily fixable. However, another contributary one might be. CS students at Cambridge typically have (at least in their first two years) between 12 and (yes, sometimes) 15 hours of lectures per week. A cautious estimate would say that to keep pace with the lecture courses, a student needs two hours of self-study per hour of lecture time, so that's 24--30 hours of self study. There's typically three or four hours of supervision contact time. Suppose each supervisor sets three past-paper Tripos questions---these are supposed to take 36 minutes to answer for a fully-prepared student, so we have to add this on top of the self-study time: 108 minutes per supervision, so call it five to seven hours. Then there'll be at least two ongoing practical series or assignments, accounting for at least six hours per week in total.

What's the sum of all this? Well, it's between 50 and 62 hours... not a particularly pleasant workload for anyone, and especially not for students who, with good reason, will be wanting to have some time left over for socialising, getting involved with extracurricular interests and so on. Not to mention eating, sleeping and the rest of it. For a University consisting of, and allegedly run by, some very smart people, it's rather shameful that those in charge of teaching either haven't done, or are flagrantly disregarding, the basic arithmetic I've just describe.

More happily, I have a feeling that extending Full Term to nine weeks is being proposed at the moment, and would definitely be progress... but only if the extra time is used to spread out the workload rather than simply packing more in. I wouldn't count on this attitude prevailing, but I live in hope.

[/teaching] permanent link contact

Powered by blosxom

validate this page