There have been a number of studies that have established that students give lower ratings to women and racialized professors even where objective measures establish that their ratings should be higher. For example, women are rated lower on "returns assignments in a timely manner" even when the women return assignments more quickly than male colleagues. And in multi-section courses with the same final exam, it is possible to look at the difference between students' initial knowledge of the subject and their final exam marks as a proxy for teaching effectiveness. Again, women and members of racialised groups are given lower ratings by students even in cases where students' improvement suggests more effective teaching.