Previous studies have indicated that the reliability of test scores composed of testlets might be overestimated by conventional item-based reliability estimation methods (R. Thorndike, 1953; A. Anastasi, 1988; S. Sireci, D. Thissen, and H. Wainer, 1991; H. Wainer and D. Thissen, 1996). This study used generalizability theory to investigate the…

Not infrequently, investigators assume that reliability for groups is greater than reliability for persons, or that the error variance for groups is less than that for persons. Using generalizability theory, it is shown that this "conventional wisdom" is not necessarily true. Examples are provided from the course-evaluation and the…

This paper reports the results of generalizability theory (G) analyses done for new writing and speaking tasks for the Test of English as a Foreign Language (TOEFL). For writing, a special focus was placed on evaluating the impact on the reliability of the number of raters (or ratings) per essay (one or two) and the number of tasks (one, two, or…

This study examines the score dependability of writing and speaking assessments from the Test of English as a Foreign Language (TOEFL) from the perspectives of univariate and multivariate generalizability theory (G-theory) and presents the findings of three separate G-theory studies. For writing, the focus was on evaluating the impact on…