Scott Carroll of UC Davis and James West of the Air Force Academy have written a paper on research that explores the teaching of older and younger professors (HT Greg Mankiw). The abstract:
In primary and secondary education, measures of teacher quality are often based on contemporaneous student performance on standardized 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.
Paul Caron of the Tax Prof blog notes this interesting finding regarding student evaluations:
We find that less experienced and less qualified professors produce students who perform significantly better in the contemporaneous course being taught, whereas more experienced and highly qualified professors produce students who perform better in the follow‐on related curriculum. ... [W]e can only speculate as to the mechanism by which these effects may operate. ...
One potential explanation for our results is that the less experienced professors may adhere more strictly to the regimented curriculum being tested, whereas the more experienced professors broaden the curriculum and produce students with a deeper understanding of the material. This deeper understanding results in better achievement in the follow‐on courses.
Another potential mechanism is that students may learn (good or bad) study habits depending on the manner in which their introductory course is taught. For example, introductory professors who “teach to the test” may induce students to exert less study effort in follow‐on related courses. This may occur because of a false signal of one’s own ability or an erroneous expectation of how follow‐on courses will be taught by other professors.
A final, more cynical, explanation could also relate to student effort. Students of low‐value‐added professors in the introductory course may increase effort in follow‐on courses to help “erase” their lower than expected grade in the introductory course.
Regardless of how these effects may operate, our results show that student evaluations reward professors who increase achievement in the contemporaneous course being taught, not those who increase deep learning. Using our various measures of teacher quality to rank‐order teachers leads to profoundly different results. Since many U.S. colleges and universities use student evaluations as a measurement of teaching quality for academic promotion and tenure decisions, this finding draws into question the value and accuracy of this practice.
I have a couple of other explanations, both revolving around the satisfaction professors get from teaching a course. The introductory material of any discipline gives students a view of the basics around which the discipline is built. The advanced courses present a more narrow view of various specialties within the discipline. Since most professors perform research within some specialty, professors of advanced courses
may be able to incorporate their research into the advanced course material. This makes it more interesting to teach.
In addition, introductory courses often are required as a part of the university core, so students take introductory courses because they have to take them,
not because they are interested in the subject material. On the other hand, students tend to take advanced courses because they find the course material, or at least the discipline, interesting. Therefore, students and professors are more likely be matched up better in the advanced courses than in the introductory courses. This also makes teaching the advanced courses more pleasurable.
