This article provides a way to determine adequate sample size for the confidence interval of covariate-adjusted mean difference in randomized experiments. The standard error of adjusted mean difference depends on covariate variance and balance, which are two unknown quantities at the stage of planning sample size. If covariate observations are…

The web tables in this report provide original and revised estimates of statistics previously published in 2007-08 National Postsecondary Student Aid Study (NPSAS:08): Student Financial Aid Estimates for 2007-08 (NCES 2009-166). The revised estimates were generated using revised weights that were updated in August 2013. NPSAS:08 data were…

The objective of this research was to determine the robustness and statistical power of three different methods for testing the hypothesis that ordinal samples of five and seven Likert categories come from equal populations. The three methods are the two sample t-test with equal variances, the Mann-Whitney test, and the Kolmogorov-Smirnov test. In…

This article examines the problem of specification error in 2 models for categorical latent variables; the latent class model and the latent Markov model. Specification error in the latent class model focuses on the impact of incorrectly specifying the number of latent classes of the categorical latent variable on measures of model adequacy as…

This article proposes a multilevel model for the assessment of school effectiveness where the intake achievement is a predictor and the response variable is the achievement in the subsequent periods. The achievement is a latent variable that can be estimated on the basis of an item response theory model and hence subject to measurement error.…

Even though rater-based judgements of clinical competence are widely used, they are context sensitive and vary between individuals and institutions. To deal adequately with rater-judgement unreliability, evaluating the reliability of workplace rater-based assessments in the local context is essential. Using such an approach, the primary intention…

This article contrasts 2 approaches to analyzing transitivity of preference and other behavioral properties in choice data. The approach of Regenwetter, Dana, and Davis-Stober (2011) assumes that on each choice, a decision maker samples randomly from a mixture of preference orders to determine whether "A" is preferred to "B." In contrast, Birnbaum…

Building on previous arguments for why educational researchers should not provide effect-size estimates in the face of statistically nonsignificant outcomes (Robinson & Levin, 1997), Onwuegbuzie and Levin (2005) proposed a 3-step statistical approach for assessing group differences when multiple outcome measures are individually analyzed…

Supplementary methods for the analysis of the Delis-Kaplan Executive Function System (Delis, Kaplan, & Kramer, 2001) are made available, including (a) quantifying the number of abnormally low achievement scores exhibited by an individual and accompanying this with an estimate of the percentage of the normative population expected to exhibit at…

The purpose of this simulation study was to assess the performance of latent variable models that take into account the complex sampling mechanism that often underlies data used in educational, psychological, and other social science research. Analyses were conducted using the multiple indicator multiple cause (MIMIC) model, which is a flexible…

Gifted students often fail to achieve at a superior level in one or more academic areas. In this reply to an article by Assouline, Nicpon, and Whiteman, the author reviews various explanations for this phenomenon, including motivation/interest, learning opportunities, and error in measuring students' ability-achievement discrepancies. The author…

The use of web-based surveys to gather information from teachers has become increasingly common primarily based on the premise that they can reduce costs. Yet, relatively, little is known about the quality or cost effectiveness of web-based versus mail surveys for teachers. To study the efficacy of web-based teacher surveys, the author randomly…

Structural equation models are increasingly used as a modeling tool for multivariate time series data in the social and behavioral sciences. Standard error estimators of SEM models, originally developed for independent data, require modifications to accommodate the fact that time series data are inherently dependent. In this article, we extend a…

This paper proposes a structural analysis for generalized linear models when some explanatory variables are measured with error and the measurement error variance is a function of the true variables. The focus is on latent variables investigated on the basis of questionnaires and estimated using item response theory models. Latent variable…

Purpose: The purpose of this study was to investigate the characteristics of missing physical activity (PA) data of children and youth. Method: PA data from the Chinese City Children and Youth Physical Activity Study ("N" = 2,758; 1,438 boys and 1,320 girls; aged 9-17 years old) were used for the study. After the data were sorted by the…