I wrote this piece on teaching a class for two reasons: 1) as a way for me to reflect on my teaching experience; 2) as advice to my fellow graduate students.
Teaching (as a graduate student)I'll start off with a bit more about my teaching experience. From Fall05 to Summer06, I was the instructor for cs2340: Objects and Design at Georgia Tech. I took this position as a graduate student for several reasons. First, my research funding had dried up and I needed a salary. Second, I felt that teaching a low-level CS class would make me more marketable as a faculty candidate, especially since my research area (Learning Sciences & Technology) is so far from mainstream computing. Third, I wanted to get some more teaching experience. I had already been the instructor for one class (cs4660: Introduction to Educational Technology), so I was not a complete novice. But, I thought that teaching a 120-person sophomore-level required class would nicely complement my experience in the 25-student senior-level elective.
As a graduate student, one of the careers you most likely will pursue is professor at a university. Even if you are primarily interested in research, you will still end up teaching classes. Teaching a class when you are still a graduate student is a good way to try out teaching.
The first time you teach a class can be incredibly taxing. When I taught my first class, I was so stressed out after every lecture that I could not get any significant work done on those days. This symptom disappeared after that first term. Assuming your first teaching experience is equally taxing, I would advise you to get it out of the way while you are still a graduate student. As a new faculty member, you will need to set up a research agenda, write grant proposals, forge connections to other faculty members, and recruit and mentor students. A taxing teaching load could seriously impair these more important activities. So, get your first teaching experience out of the way as a graduate student. Along those same lines, do not expect to make major progress on your research when you are teaching for the first time.
Unfortunately, it is not always easy to get the opportunity to be an instructor. First, you should take some small steps towards that goal. Begin by volunteering to lecture for others. All faculty members have times when they need someone to substitute for them, as they are away for conferences, religious holidays, etc. Let your advisor and other people in your area know that you are willing to fill in. If you are a teaching assistant, ask to lecture a class, even if the instructor will not be absent; most instructors are more than happy to sit in and give you notes afterwords.
When you are ready to teach your first class, begin to seek out such opportunities. These may not come to you right away, but they are out there. In the area of Learning Sciences and Technology, advanced graduate students have often taught the introductory class for undergraduates (cs4660). Similar opportunities may be open in other areas. The best way to be considered for these positions is to let others know that you are interested ahead of time. Let your advisor know that you are interested. Let the area advisor know you are interested. Even if the general policy of the department is to only have faculty teach classes, there are often exceptions. For instance, it occasionally happens that a faculty member leaves Georgia Tech. Somebody has to teach the class they were scheduled to teach and the other faculty are already scheduled for other classes; given no other alternatives, the administration will gladly take a graduate student for this position. If they already know that you are interested, you'll probably be the first person they contact.
As far as teaching your first class, there are a few things to keep in mind:
Unfortunately, there are also real negatives to teaching. First, for each great student, you will have several terrible students who do not want to put forth the effort and just demand a (good) grade. These can easily drain you of any optimism. Second, at a research university, teaching is not highly valued. People are not rewarded for good teaching. At the College of Computing, many of those faculty members that received the faculty teaching award before their tenure case came up were later denied tenure. It was partially for this reason that I decided not to pursue a professorship at a research university. I would have a hard time being simultaneously a good teacher and a good researcher. I am not willing to compromise on being a good teacher; therefore, my prospects would be fairly dim at a research university. Third, teaching can get pretty boring. Initially, you have to figure out how to convey content to your specific audience. It can be an engaging intellectual challenge. As you start to teach the same class repeatedly, that challenge diminishes. So, I decided not to pursue a teaching career at a teaching school either. It would get boring after a couple of years. To summarize, after teaching several semesters and getting good at it, I realized that I didn't want to teach. I'm glad that I figured this out before I got a professorship.
In the end, that's the kind of experience you want to get out of teaching as a graduate student. First, you want to determine whether teaching is for you. Second, you want to get some experience doing it to get better (more effective and more efficient) at it. While teaching experience is not necessary for landing a research university position, it doesn't hurt either. When I interviewed at research universities, all questions about teaching immediately went away when they learned that I already had teaching experience.