@ReginaldOhLaw the premise of this study is that the cookies are of course unrelated to how the teachers should be evaluated, and thus distort the results. However the awkwardly passive description in the abstract doesn’t tell us whether the students knew the teacher had nothing to do with the cookies. If I thought my teacher was thoughtfully providing said cookies (or yes, pizza) for us, I would consider that *highly relevant* to several dimensions of teacher rating.