Grades at US colleges and universities have increased precipitously over the last 50 years, suggesting that their signalling power has become attenuated. Moreover, average grades have risen disproportionately in some departments, implying that weak students in departments with high grades may obtain better class ranks than strong students in departments with low grades. Using a unique data set, we show that Colby College has experienced both trends and that variation in student ability does not fully explain variation in grades awarded in different departments. We then propose a simple alternative measure of calculating class ranks based on z-scores, and demonstrate that this relative measure of rank mitigates the bonus (penalty) associated with taking courses in departments with high (low) grading distributions. (Contains 5 notes, 1 figure and 5 tables.)