Tends to reward entertaining or flashy presentations rather than straightforward yet valuable ones. Discourages innovation, because students usually rate highly the teaching formats that they've seen before. An important point concerning student course evaluations is the need for a variety of evaluation forms for a variety of course types. For example, the Oberlin Physics Department uses different forms for lecture and laboratory courses. Teaching evaluation surveys from course alumni.
Alumni respond with perspective.
Low response rate. Hard to do. Delayed feedback to teacher. Tends to reward memorable presentations rather than straightforward yet valuable ones. Alumni are evaluating events in their distant pasts, so comments are likely to be colored and vague.