Using z-scores to evaluate accounting students: a test of Weinstein’s suggestion

Based on analysis using hypothetical data, Weinstein suggested that z-scores should be used in the determination of accounting students’ grades. The computation of z-scores mitigates the subjectivity caused by differences in the variances of the individual components that make up the total points for the course. We tested Weinstein’s suggestion using actual data to determine the degree to which subjectivity resulting from different variances influenced grades based on a total point distribution. The effect on actual final letter grades assigned was determined by comparing the rankings in grade distributions based on total points versus rankings based on z-scores. Findings show minimal overall effects on letter grade differences between total point and z-score-based methods. Because the results using actual data in our study found smaller differences than suggested by Weinstein’s hypothetical data, our findings do not indicate a compelling need to use a z-score standardization method in determining students’ grades. However, since using z-scores is easy and final grade rankings differed in some cases, instructors might find it useful to compute z-scores in addition to their normal grading procedures.