With the elimination of mandatory retirement, the average age of college and university faculty members has increased. While this has raised some concerns, relatively little research has tried to measure the impact of this aging on productivity inside the classroom. Using data from the RateMyProfessors.com website for a large sample of instructors in a broad cross-section of colleges and universities, we find that age does affect teaching effectiveness, at least as perceived by students. Age has a negative impact on student ratings of faculty members that is robust across genders, groups of academic disciplines and types of institutions. However, the effect does not begin until faculty members reach their mid-forties and does not seem to increase even when they reach the former retirement ages of 65 or 70. Moreover, the quantitative impact of age on student ratings is small and can be offset by other factors, especially the physical appearance of professors and how easy students consider them to be. When we restrict our sample to those professors deemed hot by student raters, the effect of age disappears completely. We conclude that ending mandatory retirement has had little impact on student perceptions of faculty quality.
That is from a new paper by Rovbert J. Stonebreaker and Gary S. Stone, via Kevin Lewis.