“is an integrated [on-going] 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...”

“is an integrated [on-going] 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...”

(Messick, 1989, p. 13)

Notes:

In 1989, Samuel Messick wrote a chapter in a standard reference text called Educational Measurement. In that chapter, he defined validity as an “integrated, evaluative judgment of the degree to which empirical evidence and theoretical rationale support the adequacy and appropriateness of inferences and actions based on test scores.” I added the term, “on-going,” to his definition because it is important to emphasize that validity is not a one–time judgment. Instead, it is a matter of continual collection of evidence to support the intended inference.