ADVERSE IMPACT AND PREDICTIVE EFFICIENCY OF VARIOUS PREDICTOR COMBINATIONS

The effects of number of predictors, predictor intercorrelations, vali dity, and level of subgroup difference on composite validity adverse i mpact ratios, and mean subgroup difference associated with various pre dictor composites, including and excluding a ''high impact'' ability m easure, were assessed. The size of subgroup differences is substantial ly smaller when low-impact predictors are combined with a high-impact predictor, but hiring ratios for majority and minority groups still in dicate a prima facie case of discrimination, using the fourth-fifths r ule for most predictor-criterion combinations. However, the validity o f a composite of alternate predictors and cognitive ability may exceed the validity of cognitive ability alone and reduce the size of subgro up differences.