Introduction

This chapter aims to introduce a substantial reconceptualization of validity, nested in an overall framework for defensible testing. It presents foundational concepts necessary for fully understanding validity, including test, inference, construct, and assessment in the social sciences. The validity of test scores—that is, the degree to which there is evidence that the scores can be taken to mean what they are intended mean—is of great consequence for all stakeholders who take, interpret, or use tests. High fidelity between variation in scores on an instrument and underlying construct variation affords some confidence that the intended inferences about the construct are appropriate. Decades of conflating the notions of test score meaning and test score use have had far-reaching and deleterious effects. Well-intentioned attempts to force concern over test use into a “unified” definition of validity that also incorporates attention to score meaning have been far from unifying.