Prior research suggests that student evaluations of teaching may depend on the average grade expected in a class. We hypothesize that, because of risk aversion, student ratings also depend on the distribution of expected grades. As predicted, student ratings at the University of Puerto Rico at Bayamon are significantly and negatively related to the variance of expected grades, implying that faculty may be able to boost their student evaluations of teaching ratings by narrowing the grade distribution. Findings are also consistent with the hypothesis that weak students place the highest value on a tight distribution of expected grades. (Contains 1 table and 14 notes.)