Tuesday, March 04, 2008

Skipping Class

Someone on the job market was wondering how many classes they could skip teaching in a typical term. As this is generally not a good question to ask during an interview, I was asked instead. Surprisingly the person wants to remain anonymous. I can't remain anonymous answering here, but then again I have tenure.

First a little math exercise that I have done since I was an undergrad. Let's take a student who take five courses per quarter. There are about 28 hours/quarter and 3 quarters. Northwestern University tuition is $35,064, coming to $83.49/hour. If you have 30 students that amounts to a bit over $25K of tuition spent on each hour you teach.

This is false math, but students are often paying the big bucks for college, including the opportunity to be taught by leading researchers in the field. You shouldn't deprive them on a regular basis.

Nevertheless sometimes you have a workshop or a conference that you don't want to miss. As a general rule you shouldn't skip enough classes that students feel cheated. There are many factors that should be taken into consideration.

  • Why are you missing the class? Do you have a family emergency? Are you a speaker at some conference? Are you visiting another university? Doing consulting work? Taking a vacation?
  • What level of class? Skipping an undergraduate class is different than skipping a graduate seminar.
  • Is there an easy make-up time that works well for the students? Can you find a replacement instructor?
  • What is the standard at your university? Could be different between schools and departments as well. My business school friends cannot miss classes. MBAs get upset easily.
  • What is your current status? Missing classes is a sign of irresponsibility. It can hurt your tenure case if you do it too much.
In the end follow your conscience. You owe it to your students to teach a good course and showing up matters.


  1. And notify, notify, notify! Nothing was more frustrating for me in undergrad than to get up early and drag myself into school only to find out the class was cancelled. It happened surprisingly often, and turned what might have been otherwise considered a nice break into impotent fury. :P

  2. you just reminded me of how much money I've lost on some useless courses so far.

    As you mentioned this kind of calculation is misleading, students may think they'll be better off without higher education. I was just thinking what could happen if I had invested $35,064 every year for the last 7 years (its my seventh year at school). I could be a millionaire :)

    Thank for the note

    PS. actually, assuming 18% annual return, the compound growth over 7 years would be $501,000. there is still some hopes!

  3. I try never to miss class. When, inevitably, there is a class I will have to miss I try to schedule the exam for that day.

    Of course, the other alternative is to find another faculty member (or your TA) to cover an occasional class you miss.

  4. $2.5K per class with your math, right, not $25K?

    But it's still a substantial amount of money.

  5. For me it depends a lot on the type of class. For a required undergraduate class, I'd find someone else to cover it if I have to miss a lecture. For a graduate seminar, skipping one or two classes is much less of a problem. And in either case I'd be much less comfortable skipping for personal reasons (a family trip) than professional ones (an algorithms conference).

  6. It can hurt your tenure case if you do it too much.

    There are good and bad reasons for missing classes. Missing classes for a family vacation or a chance to get away early for a weekend is not OK. Missing classes to serve on an NSF panel, to publicize your research via conferences or by giving talks at other universities is more than OK. If you are a pre-tenure faculty member and you aren't skipping some classes for these good reasons then you are making a mistake.

    There is the classic 'tenure tour' to publicize your research to potential letter writers but it is even better, within reason, to do this all along, if you can. That way, people will learn more than just a single snapshot of your research and it will lower the stress near tenure time. Outside of publicizing your work, engagement at conferences is valuable for obtaining fresh research ideas that will be beneficial to you in the long run.

    It is more of a mistake to think that you are so essential to your classes that you can't skip them. I tended to think this too much myself. It is important to be engaged and ensure that what is covered in your absence is well thought out so that students don't feel abandoned. In fact, giving your grad TA a chance to teach may be part of their graduate training, which is part of your job, too. Personally, I've found that 10% of classes is a fairly hard upper bound for me to comfortably maintain engagement. Others may have a different sense. {I don't recommend canceling undergrad classes but it is OK to do this for classes aimed at Ph.D. students, who will better appreciate the reasons -- and for whom the cash flow is probably in the other direction.)

  7. What a coincidence! I wrote something on the same theme this weekend, and just posted it (after getting scooped here!).

    In a regular semester, I'll usually miss 2 or so classes, and I'll get my grad student(s) or someone else to cover whenever possible. This semester I may miss 4 (cancelling one), and I feel bad about it already. But as I say in my post, there seem to be growing numbers of reasons why I have to miss class...