Why my department hopes I do not die this spring

Alice is scheduled to teach X in the Spring.

Then Alice CAN"T! (illness, death, or some other reason)

What is the department to do?

1) If its an undergraduate class than likely there are other people who are QUALIFIED. Perhaps a grad student, perhaps a postdoc, perhaps someone borrowed from another dept (Math for a theory course for example), perhaps a teacher of another section of the course, perhaps a retired teacher in the area. Might be rough because of the short notice. In Math this is easier since the courses are more standardized.

2) If its a graduate class then either

a) Its still something that someone else could teach. The set of people is smaller but might be nonempty. 

b) Nobody else can teach it. Still, its a graduate class, so its small, so it can be cancelled and the students can probably find other courses to take.

There is another positive aspect to this negative situation: If nobody else can teach it then probably the entire department is small, so even more likely that the class is small.

If I die this semester then the department will be faced with the perfect storm:

a) I am teaching a graduate course that would be a lot of work for someone else to get up to speed:Ramsey Theory. (I do have good slides, so that might help.)

b) There are around 30 students taking it. (There are around 30 in most of the graduate courses, and more in the AI graduate courses.)

SO, what would they do? 

1) Cancel it. There are a few other theory grad courses the students could take, and some might want to take a non-theory course. Still awkward since those courses are already fairly full.

2) Have someone teach a similar course, like Prob method (the only part of Ramsey Theory that Lance thinks is worthwhile, see here) or combinatorics. This would be a lot of work so it may be hard to find someone who BOTH is qualified AND wants to. Perhaps a grad student, though I think we try to avoid having grad students teach grad courses. Then again, desperate times call for desperate measures. Perhaps a former grad student who is still in the area geographically and mathematically. 

I've been talking about the teacher being unable to teach the course BEFORE it begins. What if the teacher becomes unavailable DURING the semester? That's even harder to deal with.  

OKAY, the above has all been abstract and the events portrayed are rare. Here are things I have SEEN happen and what was done

1) Someone hired as a lecturer to start in the spring ends up being unable to come for the spring. This was found out in November. They were going to teach 2 ugrad courses. 2 profs did an overload.

2) Someone who was going to teach a grad course ended up being unable to do so. This was found out in December. That teacher really did have a former grad student in the area who was available and qualified. Lucky!

3) In December a teacher ends up being unable to teach with 2 lectures to go, and the final to be administered and graded. Another teacher (who has taught that course) takes over, but this is not a big deal since its not much work to finish the course. 

4) A teacher knows ahead-of-time that they won't be able to teach for 4 weeks. Two other teachers agree to do the course in that teachers absence. 

None of  the above are ideal, but solutions were found that did work (for some definition of worked) But I do wonder if there will come a time when no solution can be found.

One piece of advice: If you are not going to be able to fulfill your commitment to teach a course, let your chairman know with a lot of lead time so they can find a solution.