Bobby Chesney asked whether it was appropriate for law professors to cancel classes in order to attend academic conferences. I suggested that the strong presumption ought to be "no," with allowances made for special cases. Michael Froomkin, James Joyner, and Steven Taylor, all reply and disagree with me. So a few thoughts seem in order.

First off, let me be clear that a strong presumption is merely a presumption. Even I am not so uncharitable as to suggest that a class can never e rescheduled for another professional obligation, however large. Felix Franfurter's example is going above and beyond the normal expectations of duty. So when Professor Froomkin says that he misses one or two classes a semster for such duties, that seems like it might be eminently consistent with my strong presumption.

Second of all, I do not doubt that attending conferences makes professors better scholars, helps them to make connections, and that this scholarship and these connections might ultimately redound to the benefit of the professor's students. My point is that legal academia is already structured to over-reward research and to under-reward teaching, so it's true that cancelling class to attend a conference may ultimately help students. But it's also true that actually showing up to teach the students helps too. It is a question of what rule can balance these interests.

Third, not all cancellations are equal. If a professor does cancel class to attend to other professional pursuits, I think the best thing to do is to bring in a substitute, whether that is a guest lecturer, another professor who teaches the same subject area (preferably with a different perspective) or something else. Obviously regular class-swaps can be arranged to make sure that everybody benefits from the trades. Trying to re-schedule make-up classes is usually cruel, putting students to a choice of unexpected or impossible last-minute schedule change or else missing out on (presumably) important material. On the other hand, cancelling class outright gives students less than they bargained for-- better than trying to reschedule class, but inferior to the substitute-teacher approach.

As Chris Lawrence points out, some classes are easier to cover than others. But so far as the law school curriculum goes, for almost every class there is somebody on the faculty who could add some on-topic thoughts that might be relevant to those thinking and working in the area, even if they aren't so close to the instructor's original vision as to keep the course "on track".

To sum up: I don't deny that conferences are important to law professors, or even that the benefits trickle down to law students who learn from them. But I do think that legal academia already rewards conference-attendance and other research-promoting activities too much, and rewards direct classroom teaching too little. So a conscientious professor would do well to put an extra thumb on the scale in favor of teaching when debating whether to cancel class and dash off to an academic conference.