Schouten and Kirkpatrick's review of evaluations of the Miller Assessment for Preschoolers' predictive validity reveals unacceptably high error rates in target population identification. Miller's response suggests flaws in their argument, Humphry and King-Thomas suggest alternative interpretations, and Schouten and Kirkpatrick respond to their…

TESTAT is a supplementary module for the popular SYSTAT statistical package for the personal computer. The program performs test analyses based on classical test theory and item response theory. Limitations and advantages are discussed. (SLD)

Ninety-five subjects observing videotaped secretaries performing well or poorly were told either to evaluate or monitor job performance. Ratings were influenced by the rater's objective. Regardless of objective, results showed a high level of covariance among the independent traits of the secretaries. (SK)

The standard error (SE) of correlations adjusted for selection with commonly used formulas was investigated. The study provides large-sample approximations of SE using the Pearson-Lawley three-variable correction formula, examines the SE under specific conditions, and compares various estimates of SEs under direct and indirect selection. (TJH)

Explores the ways in which error in measurement related to educational standards and the classification of people in educational settings is obscured in most of the practical events involving the assessment of individuals. Establishes the centrality of the measurement of educational standards to the "production" and control of the individual in…

Expands upon the concepts of precision and accuracy at a level suitable for general chemistry. Serves as a bridge to the more extensive treatments in analytical chemistry textbooks and the advanced literature on error analysis. Contains 22 references. (DDR)

Shares examples of reports of uncertainties that exceed the guideline of one or two significant figures. Points out that scientists should take great care in deciding on the appropriate form for reporting their results. (DDR)

Describes procedures for calculating conditional standard error of measurement (CSEM) and reliability of scale scores and classification of consistency of performance levels. Applied these procedures to data from the American College Testing Program's Work Keys Writing Assessment with sample sizes of 7,097, 1,035, and 1,793. Results show that the…

This simulation study investigated the robustness of structural equation modeling to different degrees of nonnormality under 2 estimation methods, generalized least squares and maximum likelihood, and 4 sample sizes, 100, 250, 500, and 1,000. Each of the slight and severe nonnormality degrees was comprised of pure skewness, pure kurtosis, and both…

The goals of this article are twofold: (a) briefly highlight the merits of residual centering for representing interaction and powered terms in standard regression contexts (e.g., Lance, 1988), and (b) extend the residual centering procedure to represent latent variable interactions. The proposed method for representing latent variable…

We evaluated the statistical power of single-indicator latent growth curve models (LGCMs) to detect correlated change between two variables (covariance of slopes) as a function of sample size, number of longitudinal measurement occasions, and reliability (measurement error variance). Power approximations following the method of Satorra and Saris…

Missing data are a common practical problem for longitudinal designs. Time-series analysis is a longitudinal method that involves a large number of observations on a single unit. Four different missing-data methods (deletion, mean substitution, mean of adjacent observations, and maximum likelihood estimation) were evaluated. Computer-generated…

The tetrachoric correlation describes the linear relation between two continuous variables that have each been measured on a dichotomous scale. The treatment of the point estimate, standard error, interval estimate, and sample size requirement for the tetrachoric correlation is cursory and incomplete in modern psychometric and behavioral…

Large numbers of rural districts have experienced sharp declines in enrollment, unlike their suburban counterparts. Accurate enrollment projections are required, whether a district needs to build new schools or consolidate existing ones. For school districts having more than 600 students, a quantitative method such as the Cohort-Survival Ratio…

In textbook treatments of enzyme inhibition kinetics, adjustment of the initial inhibitor concentration for inhibitor bound to enzyme is often neglected. For example, in graphical plots such as the Dixon plot for estimation of an inhibition constant, the initial concentration of inhibitor is usually plotted instead of the true inhibitor…