Abstract

"The greatest social benefit will come from applied research if we can find for each individual the treatment to which he can most easily adapt. This calls for the joint application of experimental and correlational methods” (Cronbach as cited by Witcherts, 2007). Recent developments in experimental industrial psychology concerning the effects of individual differences on test performance and efforts to increase validity, reliability and minimise bias have contributed to the understanding of the nature of group differences in achievement and intelligence test scores. This has been made possible by the introduction of measurement equivalence (ME) techniques that are used in psychometric evaluation.

Key words: Measurement, equivalence, invariance, psychological evaluation.