New research by Florian Hoffmann and Philip Oreopoulos
) tells us how to judge teaching ability:
subjective teacher evaluations perform well in reflecting an instructor's influence on students while objective characteristics such as rank and salary do not. Whether an instructor teaches full-time or part-time, does research, has tenure, or is highly paid has no influence on a college student's grade, likelihood of dropping a course or taking more subsequent courses in the same subject. However, replacing one instructor with another ranked one standard deviation higher in perceived effectiveness increases average grades by 0.5 percentage points, decreases the likelihood of dropping a class by 1.3 percentage points and increases in the number of same-subject courses taken in second and third year by about 4 percent.
If universities like Harvard take this research seriously when making promotion decisions, they will give less weight to research and more to student evaluations than they have historically.