Although there exists an extensive amount of research on subscores and their properties, limited research has been conducted on categorical subscores and their interpretations. In this paper, we focus on the claim of Feinberg and von Davier that categorical subscores are useful for remediation and instructional purposes. We investigate this claim…

We compared coefficient alpha with five alternatives (omega total, omega RT, omega h, GLB, and coefficient H) in two simulation studies. Results showed for unidimensional scales, (a) all indices except omega h performed similarly well for most conditions; (b) alpha is still good; (c) GLB and coefficient H overestimated reliability with small…

Simulations were conducted to examine the effect of differential item functioning (DIF) on measurement consequences such as total scores, item response theory (IRT) ability estimates, and test reliability in terms of the ratio of true-score variance to observed-score variance and the standard error of estimation for the IRT ability parameter. The…

The purpose of this study was to examine the impact of dimensionality, common-item set format, and different scale linking methods on preserving equity property with mixed-format test equating. Item response theory (IRT) true-score equating (TSE) and IRT observed-score equating (OSE) methods were used under common-item nonequivalent groups design.…

The idea of test consistency is illustrated, with reference to two sets of test scores. A mathematical model is used to explain the relative consistency and relative inconsistency of measurements, and a means of indexing reliability is derived using the model. Practical aspects of estimating reliability are considered. (TJH)

A simple stochastic model is formulated in order to determine the optimal time between the first test and the second test when the test-retest method of assessing reliability is used. A forgetting process and a change in true score process are postulated. Some numerical examples and suggestions are presented. (Author/JKS)

This article studies the ordinal reliability of (total) test scores. This study is based on a classical-type linear model of observed score (X), true score (T), and random error (E). Based on the idea of Kendall's tau-a coefficient, a measure of ordinal reliability for small-examinee populations is developed. This measure is extended to large…

Shows that the Harris factors of R have psychometric properties similar to those discussed by Kaiser and Caffrey (1965) and Bentler (1968). Specifically it is shown that the Harris factors of R maximize a lower-bound to the reliability of a composite measure derived by Guttman (1945). (Author/RC)

Examines the effects of four parameters on the accuracy of test equating under a relaxed definition of test form equivalence. The four parameters studied were sample size, test form length, test form reliability, and the correlation between true scores of the test forms to be equated. (CK)

The consequences of the assumption that the expected score is equal to the true score are shown and alternatives discussed. (MS)

Reliability maximizing weights are related to theoretically specified true score scaling weights to show a constant relationship that is invariant under separate linear tranformations on each variable in the system. Test theoretic relations should be derived for the most general model available and not for unnecessarily constrained models.…

A model is proposed for the description of ordinal test scores based on the definition of true score as expected rank; its deviations are compared with results from classical test theory. An unbiased estimator of population true score from sample data is calculated. Score variance and population reliability are examined. (Author/BJG)

This paper is aimed at demonstrating that Charles Spearman postulated neither a platonic true-error distinction nor a requirement for constant true scores under repeated measurement. (Author/RC)