Often, when I get curious about an economist I hear about or who asks me to friend him (I’ll use “him” to stand for “him/her”) on Facebook, I do a Google search and his ratings on “Rate My Professor” show up. So I often go to the ratings to see what students say. I know I’m getting a biased sample for which the particular biases are unknown but, still, it’s some information.

After having done this for over 5 years, I’ve realized something that I should’ve realized much sooner. The raters virtually never discuss anything about what they’ve learned. The typical comment is about what you need to do to get an A or a B: things like go to class, pay close attention, do the readings, don’t do the readings but take good notes, do the homework, etc. What’s missing is anything like: I learned a lot, this class changed my way of thinking, I particularly liked how he treated subject X, etc.

As I said, this is a biased sample. Maybe the only people who go to rate a professor are people who want to give other students tips about how to get grades. But even if that’s what’s going on, it’s telling. And it’s medium to strong evidence for Bryan Caplan’s thesis that higher education is 80 percent about signaling.