- Subject index
Validity is the hallmark of quality for educational and psychological measurement. But what does quality mean in this context? And to what, exactly, does the concept of validity apply? These apparently innocuous questions parachute the unwary inquirer into a minefield of tricky ideas. This book guides you through this minefield, investigating how the concept of validity has evolved from the nineteenth century to the present day. Communicating complicated concepts straight forwardly, the authors answer questions like: What does ‘validity’ mean? What does it mean to ‘validate’? How many different kinds of validity are there? When does validation begin and end? Is reliability a part of validity, or distinct from it? This book will be of interest to anyone with a professional or academic interest in evaluating the quality of educational or psychological assessments, measurements and diagnoses.
Chapter 1: Validity And Validation
Validity And Validation
Validity is the hallmark of quality as far as testing is concerned, being the ‘single most important criterion’ for evaluating a test (Koretz, 2008: 215). At this level of generality, the many sub-communities of scientists and practitioners that comprise the field of educational and psychological measurement are probably in agreement. However, when interrogated further, this relatively bland consensus can be shown to conceal many different perspectives on the meaning of validity, reflecting claims at a variety of levels, for example, that:
- it is possible to measure an attribute accurately using test scores (validity as a measurement concept); or
- it is possible to make accurate and useful decisions on the basis of test scores (validity as a measurement and decision-making concept); or
- it is acceptable to implement a testing policy (validity as a ...