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…

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…

Using data from the final two rounds of the Early Childhood Longitudinal Study, Birth Cohort (ECLS-B), a longitudinal study begun in 2001, this First Look provides a snapshot of the demographic characteristics, reading and mathematics knowledge, fine motor skills, school characteristics, and before- and after-school care arrangements of the cohort…

One of the most important effect sizes used in meta-analysis is the standardized mean difference (SMD). In this article, the conditions under which SMD effect sizes based on different measures of the same construct are directly comparable are investigated. The results show that SMD effect sizes from different measures of the same construct are…

The term "gifted" implies a permanent superiority. However, the majority of children who score in the top few percentiles on ability and achievement tests in 1 grade do not retain their status for more than a year or 2. The tendency of those with high scores on one occasion to obtain somewhat lower scores on a later occasion is one…

As part of No Child Left Behind (NCLB) legislation, many states are using confidence intervals to determine a range of scores for evaluating a school system. More specifically, the states are employing confidence intervals to help minimize measurement error in determining a school system's performance. The methodology and techniques employed in…

As performance-based assessments have gained wider use, there are increasing concerns about their dependability. This study is a synthesis of existing studies regarding the reliability or generalizability of performance assessments. The meta-analysis involves summarizing, examining, and evaluating research findings. Articles on the dependability…