University of Queensland
The author's conclusion is that "These results on student evaluations are only depressing if you thought they were an objective measure of teaching quality". But who in any service delivery industry would think a consumer survey is an objective measure? Like any consumer survey, the results will reflect the biases of those surveyed. That the quantitative results are consistent is a positive result, and should be enough to use the surveys as a early warning indicator of a problem with a course or teachers.
If the numbers for one course or teacher is very low, then there is a reason to check why. But sifting through what students write on surveys to decide if one teacher is slightly better than another is nuts. Also such a survey should have nothing to do with the amount of time a teacher spends teaching. They should spend the time needed to meet learning outcomes for students, which have nothing to do with a popularity poll.