A new metastudy of more than 100 research articles on student evaluations of teaching (SET) finds that evaluations are impacted by characteristics unrelated to actual instructor quality. Classes with lighter workloads or higher grading distributions do have better scores from students. Students also rate nonelective and quantitative courses lower. Evaluations for upper-level, discussion-based classes are higher than those for larger introductory courses.

Ratings vary across disciplines, with students rating natural science courses lowest and humanities highest. Oh, and bringing chocolate cookies to class actually results in higher ratings.

As for equity bias, the study finds that factors including an instructor’s gender, race, ethnicity, accent, sexual orientation or disability status affect impact student ratings. Compared to women, male instructors are perceived as more accurate in their teaching, more educated, less sexist, more enthusiastic, competent, organized, easier to understand, prompt in providing feedback, and they are less penalized for being tough graders, according to the study. In studies involving identical online course designs involving a hypothetical male or female instructor, students rate the male instructor more highly than the female one.