Saturday, November 17, 2007

Cause and Effect?

The first time I taught a particular physics course, the class schedule was three days per week, 50 minute class meetings. I designed my exams for that length of time. The students did well and most students finished comfortably within the 50 minute period. The next time I taught the same course, the class met two days per week, 75 minute class meetings. Another difference was that the previous class was a small class at a community college, and the second class was approaching 200 students at a university. Anyways, I gave the same exams, so I could contrast performance. What surprised me was how many students took the whole time and the class as a whole did worse. The next time I taught the course was the same setup - large class, two days at 75 minutes each, at the university. This class also thought the exams were too long, but did really well overall. I'm currently teaching this same course to a small class at a community college, which meets two days per week, 2 hours each time. These students find the exams too long, although these are the same design, and in some cases the same questions, as the very first time I taught the course. In fact, the reason why I'm posting this now is that I had two students this week need MORE than the two hours to finish the exam.

So, what's going on here? I've come up with some possible issues:

  • First time through, I graded everything. Homeworks, exams, etc... The other times, TAs and/or online homeworks were incorporated.
  • The most recent section is made up of slightly different majors.
  • Test-taking expands to fill the available time.
  • Some classes are just better than others.

I've eliminated some possibilities:

  • Small class vs. large class - I've had both do well.
  • Community college vs. university - I've had both do well.

Any thoughts?


SarahP said...

Also maybe the 'blink' phenomenon?

(I haven't read Blink, but J has and told me about it. The idea is that people's initial gut reactions to things are more often correct than their careful reconsiderations.

So I wonder if having to take a test at speed makes people accept their own 'blink' answers without having time to rethink them too much...?

Anyway, J has noted this in his classes. Some people leave really early, and they tend to do as well or better than the people he has to wrest the test away from at the end of the period...

Jackie M. said...

Got me! I'm going to go with the "some classes are just better than others" phenomenon...

Dr. Lisa said...

Jackie is naughty!

Sarah, I'm glad that J has noticed a similar phenomenon. My astronomy quizzes are partially multiple choice, and the borderline students often change from the correct to incorrect answer before turning the quizzes in. Of course, those are the same students who would freak out if I gave them less time. Sigh.

Pat. said...

Does it have to do with time of year?
Regardless of whether that had any effect, I'm gonna go with "exams will fill the alloted time no matter what" effect. I mean, who EVER wants to finish too early and wonder if they missed something all week.

Dr. Lisa said...

If it hasn't already been done, there is a lot of interesting psychology to study written in the body language of the students during exams. The tendency of the whole class to tense up after the first test-taker leaves is amazing to see.