A recent study found that students’ evaluation of teaching quality at universities drops by about half a standard deviation when the effectiveness of the teacher in improving students’ performance increases by one standard deviation. In other words: the better the teacher, the worse the evaluation. This is mainly due to the extra-effort that good teachers require from their students. The weather also proves to be a determinant of evaluation results. Overall, these findings cast doubts on the evaluation practices of universities, both with regard to current and prospective teachers.