Does Professor Quality Matter?

That's the title of the new lead article (gated) in the Journal of Political Economy, by Scott E. Carrell and James E. West, and here is the answer:

In primary and secondary education, measures of teacher quality are often based on contemporaneous student performance on standard-ized achievement tests. In the postsecondary environment, scores on student evaluations of professors are typically used to measure teaching quality. We possess unique data that allow us to measure relative student performance in mandatory follow-on classes. We compare metrics that capture these three different notions of instructional quality and present evidence that professors who excel at promoting contemporaneous student achievement teach in ways that improve their student evaluations but harm the follow-on achievement of their students in more advanced classes.

I found this to be an impressive piece of research.  Here is one summary sentence:

The overall pattern of the results shows that students of less experienced and less qualified professors perform significantly better in the contemporaneous course being taught.  In contrast, the students of more experienced and more highly qualified introductory professors perform significantly better in the follow-on courses.

Here is an ungated version, it may or may not be exactly the same.