The Graduate Management Admission Council (GMAC) Validity Study Service was created to enable graduate schools of management to investigate the adequacy of the devices and procedures they use for selection purposes and to facilitate the accumulation and summary of data from many individual graduate management schools. Participating schools are required to provide information on three standard predictors Graduate Management Admission Test (GMAT)-Verbal and GMAT-Quantative scores, and undergraduate grade point average) and one standard criterion (first year grade average in management school). In addition, each school may specify optional subgroupings, predictors, and criteria relevant to its admissions process. From 1978-79 through 1980-81, 85 separate studies have been conducted through the Validity Study Service. This report provides: (1) a descriptive summary of the validity of GMAT scores and undergraduate grade point average as predictors of first year grade point average in management school; and (2) a categorization of optional variables designated by individual schools along with the correlational analyses for the most frequently specified variables. For nearly all of the included studies, the use of both undergraduate grades and GMAT scores together results in better prediction of first year average, compared to the use of either preadmission measure alone. (Author/BS)