Everyone is jumping on the bandwagon, including Tyler Cowen, Greg Mankiw, and even Sandeep. They are all trumpeting this study whose bottom line is that student evaluations of teachers are inversely related to the teacher’s long-run added value. The conclusion is based on two findings. First, if my students do unusually well in my class they are likely to do badly in their followup classes. Second, if my students evaluate me highly it is likely that they did unusually well in my class.
I am not jumping on the bandwagon. I have read through the paper and while I certainly may have overlooked something (and please correct me if I have) I don’t see any way the authors have ruled out the following equally plausible explanation for the statistical findings. First, students are targeting a GPA. If I am an outstanding teacher and they do unusually well in my class they don’t need to spend as much effort in their next class as those who had lousy teachers, did poorly this time around, and have some catching up to do next time. Second, students recognize when they are being taught by an outstanding teacher and they give him good evaluations.
The authors of the cited study are every time quick to jump to the following conclusion: older, experienced teachers, and especially those with PhD’s know how to teach “lasting knowledge” whereas younger teachers “teach to the test.” That’s a hypothesis that sounds just right to all of us older, experienced teachers with PhD’s. But is it any more plausible than older experienced teachers with tenure don’t care about teaching and as a result their students do poorly? Not to me.
Dear 310-2 students who will be filling out evaluations this week: please don’t hold it against me that I am old, experienced, and have a PhD.