My colleague Heather Whitney has a post up at ProfHacker about one aspect of student evaluations: their occasional lack of truthfulness. Let me add my two cents:A year ago, as some readers of this blog may recall, I spent some time in the hospital. My classes that semester met on Tuesdays and Thursdays, and as a result of illness I missed four classes: two weeks total, in a fourteen-week semester. A lot to miss! — but perhaps not enough to warrant students writing on their evaluations, “It’s hard to evaluate this class because we hardly ever met,” or “It’s not Dr. Jacobs’s fault for being sick, but the fact that he missed most of the semester really hurt the success of this class.”I also recall, a couple of years back, some students complaining on their evaluations that they got poor grades on their papers because I didn’t give them any guidance — even though before turning in the final draft of their papers they had to submit (a) a proposal for the paper, to which I responded in writing with detailed suggestions, and then (b) a complete draft of the paper, to which I also responded in writing. If this was not “guidance,” I wonder what would have been.I can only explain this phenomenon — which is consistent among a minority of students — by speculating that some students think that evaluations are an opportunity not for them to speak truthfully, according to any naïvely “objective” or dispassionate model of truth, but rather for them to share their feelings — whatever those feelings happen to be at the moment. And at the end of a long and stressful semester, those feelings will sometimes be rather negative. This is one of the many reasons why student evaluations as they are typically solicited and offered are useless, or worse than useless — and I speak as someone with a long history of very positive student evaluations.Thus for a long time I have recommended, to anyone who will listen and to many who will not, that evaluations for a given course be solicited at least one full semester after the course is completed, when students are less emotionally involved in it. A year or more after would be even better. We might get fewer responses, especially from students who have graduated, but they would be better responses.Whenever I make this suggestion, the first response I get is always the same: “But a semester [or a year] later, they won’t remember anything from the class!”“That would be something worth knowing,” I reply.