It is incorrect to say "the test is reliable" because reliability is a function not only of the test itself, but of many factors. The present paper explains how different factors affect classical reliability estimates such as test-retest, interrater, internal consistency, and equivalent forms coefficients. Furthermore, the limits of classical test…

The application of generalizability theory to the reliability and error variance estimation for performance assessment scores is discussed. Decision makers concerned with performance assessment need to realize the restrictions that limit generalizability such as limitations that lead to reductions in the number of tasks possible, rater quality,…

A measurement approach called generalizability theory (G-theory) is an important alternative to the more familiar classical measurement theory that yields less useful coefficients such as alpha or the KR-20 coefficient. G-theory is a theory about the dependability of behavioral measurements that allows the simultaneous estimation of multiple…

This study is an attempt at a cohesive characterization of the concept of essay reliability. As such, it takes as a basic premise that previous and current practices in reporting reliability estimates for essay tests have certain shortcomings. The study provides an analysis of these shortcomings--partly to encourage a fuller understanding of the…