This article extends multivariate generalizability theory (MGT) to tests with different random-effects designs for each level of a fixed facet. There are numerous situations in which the design of a test and the resulting data structure are not definable by a single design. One example is mixed-format tests that are composed of multiple-choice and…

Broadly conceived, reliability involves quantifying the consistencies and inconsistencies in observed scores. Generalizability theory, or G theory, is particularly well suited to addressing such matters in that it enables an investigator to quantify and distinguish the sources of inconsistencies in observed scores that arise, or could arise, over…

This article provides general procedures for obtaining unbiased estimates of variance components for any random-model balanced design under any bootstrap sampling plan, with the focus on designs of the type typically used in generalizability theory. The results reported here are particularly helpful when the bootstrap is used to estimate standard…

Estimating standard errors of estimated variance components has long been a challenging task in generalizability theory. Researchers have speculated about the potential applicability of the bootstrap for obtaining such estimates, but they have identified problems (especially bias) in using the bootstrap. Using Brennan's bias-correcting procedures…

Reviews some of the more salient conceptual features of generalizability (G) theory. Provides a framework for considering some misconceptions about G theory. Focuses on particularly prevalent or serious misconceptions. G theory provides a rich conceptual framework and tools for working with a defined universe, but it does not tell an investigator…

Provides a comprehensive and integrated treatment of both conditional absolute standard errors of measurement (SEM) and conditional relative SEMs from the perspective of generalizability theory. Illustrates the approach with examples from commercial standardized tests. Examples support the conclusion that both types of conditional SEMs tend to be…

Reviews relevant aspects of generalizability theory related to performance assessments and discusses the role of various facets in assessing the generalizability of performance assessments. Also considers some popular estimates of reliability for performance assessments from the perspective of generalizability theory. (SLD)

In assessment programs where scores are reported for individual examinees, it is desirable to have responses to performance exercises graded by more than one rater. If more than one item on each test form is so graded, it is also desirable that different raters grade the responses of any one examinee. This gives rise to sampling designs in which…

The history of generalizability theory (G theory) is told from the perspective of one researcher's experiences, describing psychometric and scientific perspectives that influenced the development of G theory and its adoption. Work that remains to be done in the field is outlined. (SLD)

Studied the sampling variability of estimated variance components using data collected over several years for a listening and writing performance assessment and evaluated the stability of estimated measurement precision. Results indicate that the estimated variance components varied from one year to another and suggest that the measurement…

Generalizability theory is used to show that the assumption that reliability for groups is greater than that for persons (and that error variance for groups is less than that for persons) is not necessarily true. Examples are provided from course evaluation and performance test literature. (SLD)

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…

A conceptual framework and heuristic model for considering the existence, magnitude, and consequences of context effects are presented through an extension of some generalizability theory concepts. Context effects are often misunderstood, and current measurement models have serious limitations for examining them. Their importance needs to be…

Purpose: Determining the valid and fair use of the interview for medical school admissions is contingent upon a demonstration of the reproducibility of interview scores. This study seeks to establish the generalizability of interview scores, first assessing the existing research evidence, and then analyzing data from a non-experimental independent…

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,…