Validity is defined by Samuel Messick as an integrated, evaluative judgment of the degree to which empirical evidence and theoretical rationales support the adequacy and appropriateness of inferences and actions based on test scores or other modes of assessment. This definition opens Messick's chapter, “Validity,” in the third edition of Educational Measurement, which is a benchmark publication in the field. Although Messick's conception of validity has generated some debate, this chapter has arguably provided the dominant scholarly representation of validity in educational measurement since its publication in 1989. Like the validity chapters in the preceding (1950, 1971) and subsequent (2006) editions of Educational Measurement (by Edward E. Cureton, Lee J. Cronbach, and Michael J. Kane, respectively), it is intended to provide guidance to those who ...