Minority Contributions to the Sat Score Turnaround: an Example of Simpson’s Paradox

Abstract

Since 1980 the decline in SAT scores has stopped and the scores have started to creep back up. The scores for white Americans have increased 8 points during this period and 15 points for non-whites. It was thus surprising to discover that the overall mean increased only 7 points. This is not an arithmetic error but rather an example of a well-known statistical phenomenon called Simpson’s Paradox. In this note we explain the paradox and describe a method that will avoid it in the future.