Differential Validity and Differential Prediction of Cognitive Ability Tests: Understanding Test Bias in the Employment Context

Abstract

Substantial mean score differences and significant adverse impact have long motivated the question of whether cognitive ability tests are biased against certain non-White subgroups. This article presents a framework for understanding the interrelated issues of adverse impact and test bias, with particular focus on two forms of test bias especially relevant for personnel selection: differential validity and differential prediction. Ethical and legal reasons that organizations should be concerned about differential validity/prediction are discussed. This article also serves as a critical review of the research literature on differential validity/prediction. The general conclusion is that available evidence supports the existence of differential validity/prediction in the form of correlation/slope and intercept differences between White and non-White subgroups. Implications for individuals and organizations are outlined, and a future research agenda is proposed highlighting the need for new, better data; new, better methods of testing for differential validity/prediction; and investigation of substantive factors causing differential validity/prediction.