GRADES AND TEST SCORES: ACCOUNTING FOR OBSERVED DIFFERENCES

Abstract

Why do grades and test scores often differ? A framework of possible differences was proposed. An approximation of the framework was tested with data on 8454 high school students. Individual and group differences in grade versus test performance were substantially reduced by focusing the two measures on similar academic subjects, correcting for grading variations and unreliability, and adding teacher ratings and other information about students. Concurrent prediction of high school average was thus increased from.62 to.90; differential prediction was reduced to.02 letter-grades. Grading variation was a major source of discrepancy between grades and test scores. The analysis suggested Scholastic Engagement as a promising organizing principle in understanding student achievement. It was defined by three types of observable behavior: employing school skills, demonstrating initiative, and avoiding competing activities. Groups differed in average achievement, but group performance was generally similar on grades and tests. If artifactual differences between the two measures are not corrected, common statistical estimates of test validity and fairness are unduly conservative. Different characteristics give grades and test scores complementary strengths in high-stakes assessment. (Key words: validity, school achievement, scholastic engagement, group differences, grading, differential prediction).