Monday, June 14, 2010
Scott E. Carrell (University of California-Davis, Department of Economics) & James E. West (U.S. Air Force Academy) have published Does Professor Quality Matter? Evidence from Random Assignment of Students to Professors, 118 J. Pol. Econ. 407 (June 2010):
(Hat Tip: Greg Mankiw.)
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.