Updating conceptions of validity and reliability.

Measurement validity is important when conducting research. This is as true for sociobehavioral research as for clinical research. Although the importance of validity is not new, its conceptualization has changed substantially in the past few decades. In the literature, there is a lack of consistency in how validity is presented. This may stem from a lack of awareness of the relatively recent changes in conceptualization of validity, the continued use of a historical framework in some educational texts, and/or the continued use of a historical framework in some training programs. This article presents a brief history of the conceptualization of validity including the progression from a perspective of related concepts of reliability and validity, to multiple types of validity, to a view of validity as a unitary concept supported by different types of evidence. This article closes by raising some important considerations about promoting use of a contemporary validity framework and associated terminology in current research, as well as in the education of future health-sciences researchers.