Using a sample of workers displaced by plant closings, a study attempted to reduce error bias in estimates of unions' effect on earnings. When estimations use the entire sample, longitudinal estimates are similar to those of cross-sectional regressions. When skill groups are estimated separately, unions have a positive effect for workers with low…

Examined the stability of the standard error of measurement and the relationship between the reliability coefficient and the variance of both true scores and error scores for 170 school districts in a state. As expected, reliability coefficients varied as a function of group variability, but the variation in split-half coefficients from school to…

Presents an Item Response Theory (IRT) method for estimating standard errors of measurement of scale scores for the situation in which scale scores are nonlinear transformations of number-correct scores. Also describes procedures for estimating the average conditional standard error of measurement for scale scores and the reliability of scale…

Although often ignored, reliability is critical when interpreting study effects and test results. Accordingly, this article focuses on the most commonly used estimate of reliability, internal consistency coefficients, with emphasis on coefficient alpha. An interpretive framework is provided for applied researchers and others seeking a conceptual…

Compared bootstrap standard errors of five item response theory (IRT) equating methods for the common-item nonequivalent groups design using test results for 1,493 and 1,793 examinees taking a professional certification test. Results suggest that standard errors of equating less than 0.1 standard deviation units could be obtained with any of the…

A decision-theoretic approach to the question of reliability in categorically scored examinations is explored. The concepts of true scores and errors are discussed as they deviate from conventional psychometric definitions and measurement error in categorical scores is cast in terms of misclassifications. A reliability measure based on…

A widely and readily applicable covariance structure modeling approach is outlined that allows point and interval estimation of scale reliability with fixed components. The procedure employs only linear constraints introduced in a congeneric model, which after reparameterization permit expression of composite reliability as a function of…

The phenomenon of nonlinear resonance (sometimes called the "jump phenomenon") is examined and second-order van der Pol plane analysis is employed to indicate that this phenomenon is not a feature of the equation, but rather the result of accumulated round-off error, truncation error and algorithm error that distorts the true bounded solution onto…

"Choice and Education across the States," published by the Heartland Institute, is an advocacy document that assigns letter grades to states based on the extensiveness of each state's school choice system. The report asserts, based on a faulty use of past research, that an increase in school choice will strengthen accountability and improve…

In this study, the authors compare the validity of three nonverbal tests for the purpose of identifying academically gifted English-language learners (ELLs). Participants were 1,198 elementary children (approximately 40% ELLs). All were administered the Raven Standard Progressive Matrices (Raven), the Naglieri Nonverbal Ability Test (NNAT), and…

Confirmatory factor analytic (CFA) procedures can be used to provide evidence of measurement invariance. However, empirical evaluation has not focused on the accuracy of common CFA steps used to detect a lack of invariance across groups. This investigation examined procedures for detection of test structure differences across groups under several…

This study is a partial replication of L. Hu and P. M. Bentler's (1999) fit criteria work. The purpose of this study was twofold: (a) to determine whether cut-off values vary according to which model is the true population model for a dataset and (b) to identify which of 13 fit indexes behave optimally by retaining all of the correct models while…

This study evaluated the impact of unequal reliability on test equating methods in the nonequivalent groups with anchor test (NEAT) design. Classical true score-based models were compared in terms of their assumptions about how reliability impacts test scores. These models were related to treatment of population ability differences by different…

Short tests containing at most 15 items are used in clinical and health psychology, medicine, and psychiatry for making decisions about patients. Because short tests have large measurement error, the authors ask whether they are reliable enough for classifying patients into a treatment and a nontreatment group. For a given certainty level,…

Evidence-based practice approaches to interventions has come of age and promises to provide a new standard of excellence for school psychologists. This article describes several definitions of evidence-based practice and the problems associated with traditional statistical analyses that rely on rejection of the null hypothesis for the…