Dependability of class means is analyzed by applying generalizability to a split-plot design with students nested within classes. Basic generalizability concepts are reviewed, and the derivation and interpretation of distinct generalizability concepts are discussed. Four generalizability coefficients are compared with each other and with the three…

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)

Using several data sets, the relative performance of the beta binomial model and two more general strong true score models in estimating several indices of classification consistency is examined. It appears that the beta binomial model can provide inadequate fits to raw score distributions compared to more general models. (TJH)

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…

An attempt is made to explore the use of subjective probabilities in the analysis of item data, especially criterion-referenced item data. Two assumptions are implicit: (1) one wants to obtain a maximum amount of information with respect to an item using a minimum number of subjects; and (2) once the item is validated, it may well be administered…

Using the assumption of randomly parallel tests and concepts from generalizability theory, three signal/noise ratios for domain-referenced tests are developed, discussed, and compared. The three ratios have the same noise but different signals depending upon the kind of decision to be made as a result of measurement. (Author/JKS)

Discusses some problems, pitfalls, and paradoxes that challenge measurement theory and practice, especially for K-12 achievement testing. Considers a number of technical issues, especially some related to reliability. Also discusses a number of practical or political issues related to validation and accountability. (SLD)

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…

When classes are the units of analyses, estimates of the reliability of class means are needed. Using classical test theory it is difficult to treat this problem adequately. Generalizability theory, however, provides a natural framework for dealing with the problem. Each of four possible formulas for the generalizability of class means is derived…

Studied longitudinal changes in performance at both the student and school district level in major content areas of a widely used norm-referenced grade-level testing program. Used data from grades 3 to 4 and from 7 to 8 of the Iowa Tests of Basic Skills (in Iowa). Reports descriptive statistics and empirical norms and reliability estimates for…

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,…

Rules, procedures, and algorithms intended to aid researchers and practitioners in the application of generalizability theory to a broad range of measurement problems are presented. Two examples of measurement research are G studies, which examine the dependability of some general measurement procedure; and D studies, which provide the data for…

Explores the relationship between measurement theory and practice, considering five broad categories of: (1) models, assumptions, and terminology; (2) reliability; (3) validity; (4) scaling; and (5) setting performance standards. It must be recognized that measurement is not an end in itself. (SLD)

Generalizability theory is used to examine the psychometric characteristics of the Listening and Writing Tests developed by American College Testing for its Work Keys program. Results with samples of 50 suggest the desirability of a minimum number of the tests' tape-recorded messages and the use of at least 2 raters. (SLD)