It has been 25 years since the publication of Schmidt and Hunter's (1977) article “Development of a General Solution to the Problem of Validity Generalization” (Journal of Applied Psychology, 62, 643661). That article, and the subsequent stream of research, debate, and discussion about the meaning of validity generalization (VG), changed the face of personnel psychology. Prior to 1977, it was assumed that a new validity study would be needed virtually every time a test or selection procedure was tried out in some new setting. After 1977, it was often argued that a new local validity study was not only not needed, but that it might even add to the confusion rather than shedding new light on the validity of the test.
Developments in validity generalization led to wholesale changes in psychologists' assumptions about what conclusions could or could not be drawn from examining the cumulative literature. Prior to 1977, researchers often despaired of making sense of substantial bodies of research, largely because of the apparent instability of results from study to study. A test or intervention that seemed to work well in one organization would appear to fail in other similar settings, and given the extensive variability in study outcomes, it seemed that few good conclusions could be gained from looking at the research literature. Psychologists who wanted to know how a test or intervention would work in some particular setting would simply have to try it out there and see. VG research suggested that