Understanding What the Numbers Mean: A Straightforward Approach to GRE Predictive Validity. ETS GRE Board Research Report No. 04-03. ETS RR-08-46

Descriptions of validity results for the GRE® General Test based solely on correlation coefficients or percentage of the variance accounted for are not merely difficult to interpret, they are likely to be misinterpreted. Predictors that apparently account for a small percentage of the variance may actually be highly important from a practical perspective. This study used 2 existing data sets to demonstrate alternative methods of showing the value of the GRE as an indicator of 1st-year graduate grades. The combined data sets contained 4,451 students in 6 graduate fields: biology, chemistry, education, English, experimental psychology, and clinical psychology. In one set of analyses, students within a department were divided into quartiles based on GRE scores and the percentage of students in the top and bottom quartiles earning a 4.0 average was noted. Students in the top quartile were 3 to 5 times as likely to earn 4.0 averages compared to students in the bottom quartile. Even after controlling for undergraduate grade point average quartiles, substantial differences related to GRE quartile remained.