Exact formulas for classical error variance are provided for Rasch measurement with logistic distributions. An approximation formula with the normal ability distribution is also provided. With the proposed formulas, the additive contribution of individual items to the population error variance can be determined without knowledge of the other test…

Previous studies have indicated that the reliability of test scores composed of testlets is overestimated by conventional item-based reliability estimation methods (S. Sireci, D. Thissen, and H. Wainer, 1991; H. Wainer, 1995; H. Wainer and D. Thissen, 1996; G. Lee and D. Frisbie). In light of these studies, it seems reasonable to ask whether the…

The primary purpose of this study was to investigate the appropriateness and implication of incorporating a testlet definition into the estimation of the conditional standard error of measurement (SEM) for tests composed of testlets. The five conditional SEM estimation methods used in this study were classified into two categories: item-based and…

Teacher efficacy has proven to be an important variable in teacher effectiveness. It is consistently related to positive teaching behaviors and student outcomes. However, the measurement of this construct is the subject of current debate, which includes critical examination of predominant instruments used to assess teacher efficacy. The present…

Researchers consistently fail to report reliability estimates for data used in their studies. This lack of reporting hinders appropriate evaluation and interpretation of data and may lead to inappropriate conclusions. Because reliability is inured to scores obtained from a test, and not the test itself, it is important to report score reliability…

This reply refers to PS 502 345 which in turn is a criticism of EJ 045 083. (CB)

Purpose of this article is to explain the fundamental nature and sources of regression toward the mean. The ultimate goal is that developmental psychologists understand regression effects well enough so that they will not make erroneous interpretations of such effects in their empirical data. (Author)

Study based on F. M. Lord's arguments in 1957 and 1959 that tests of the same length do have the same standard error of measurement. (CB)

Computed confidence intervals for the Wechsler Adult Intelligence Scale-Revised for the Verbal, Performance, and Full Scale IQ scores. Reports IQ intervals for the 85 percent, 90 percent, 95 percent, and 99 percent levels of confidence for each of the nine standardization sample age groups and the entire sample. (Author)

The purpose of this article is to review applications of reliability formulas and to recommend more appropriate methods of determining the reliability of affective instruments. (SK)

Formulas for the standard error of measurement of three measures of change (simple differences; residualized difference scores; and a measure introduced by Tucker, Damarin, and Messick) are derived. A practical guide for determining the relative error of the three measures is developed. (Author/JKS)

Both the binomial and beta-binomial models are applied to various problems occurring in mental test theory. The paper reviews and critiques these models. The emphasis is on the extensions of the models that have been proposed in recent years, and that might not be familiar to many educators. (Author)

A jackknife-like procedure is developed for producing standard errors of estimate in maximum likelihood factor analysis. Unlike earlier methods based on information theory, the procedure developed is computationally feasible on larger problems. Examples are given to demonstrate the feasibility of the method. (Author/JKS)

Huynh (1976) suggested a method of approximating the reliability coefficient of a mastery test. The present study examines the accuracy of Huynh's approximation and also describes a computationally simpler approximation which appears to be generally more accurate than the former. (Author/RL)

McNemar's discussion of error reduction in a mixed two-group design fails to provide an algebraic presentation of this error reduction. This paper presents not only the algebraic development of the error term but shows that under certain conditions mixing may increase experimental error. (Author)