Generalizability Theory

Generalizability theory consists of a conceptual framework and a methodology that enable an investigator to disentangle multiple sources of error in a measurement procedure. The roots of generalizability theory can be found in classical test theory and analysis of variance (ANOVA), but generalizability theory is not simply the conjunction of classical theory and ANOVA. In particular, the conceptual framework in generalizability theory is unique. This framework and the procedures of generalizability theory are introduced and illustrated in this instructional module using a hypothetical scenario involving writing proficiency.