To date, small sample problems with latent growth models (LGMs) have not received the amount of attention in the literature as related mixed-effect models (MEMs). Although many models can be interchangeably framed as a LGM or a MEM, LGMs uniquely provide criteria to assess global data-model fit. However, previous studies have demonstrated poor…

Cluster randomized trials involving participants nested within intact treatment and control groups are commonly performed in various educational, psychological, and biomedical studies. However, recruiting and retaining intact groups present various practical, financial, and logistical challenges to evaluators and often, cluster randomized trials…

The distance between nonparametric and parametric item characteristic curves has been proposed as an index of goodness of fit in item response theory in the form of a root integrated squared error index. This article proposes to use the posterior distribution of the latent trait as the nonparametric model and compares the performance of an index…

For the past 25 years, methodological advances have been made in missing data treatment. Most published work has focused on missing data in dependent variables under various conditions. The present study seeks to fill the void by comparing two approaches for handling missing data in categorical covariates in logistic regression: the…

To test the use of Bayes's theorem to adjust for nonresponse bias, 600 hospitals were used in a simulated sample survey. On the basis of known information on five variables, Bayes's formula correctly predicted the status of 92 of the 100 "nonrespondents" relative to a sixth variable. (Author/BW)

Properties of the Spearman correction for attenuation were investigated using Monte Carlo methods, under conditions where correlations between error scores exist as a population parameter and also where correlated errors arise by chance in random sampling. Equations allowing for all possible dependence among true and error scores on two tests at…

Bechhofer's procedure for selecting the population with the largest mean from among several populations with known variances is discussed as it applies to the problem of selecting the bivariate normal population with the largest correlation coefficient. Tables of appropriate sample sizes are provided and an example is discussed. (Author/JKS)

Paper covers the first part of a study that is concerned with the inferential accuracy of the formulas that have been developed to correct'' several sample statistics for the effects of restriction of range. (Authors)

Major interest is the derivation of a mathematical formulation and a demonstration of the effects of pooling two subgroups on the total group correlation coefficient, and additionally, a procedure to guide the decision concerning the pooling of data for the purpose of calculating a single correlation coefficient. (Author/RC)

Research tested the hypothesis that homogeneous subject groups would produce test responses with better homogeneity indices than those of the parent sample from which they were drawn. (Author)

In this paper, tables for the appropriate sample sizes are presented and discussed in the context that the determination of the effect size must precede the determination of the sample size. (Author/PN)

Examines the similarity between the coordinates which resulted when correlations were used as similarity measures and the factor loadings obtained by factor analyzing the same correlation matrix. Real data, a set of error free data, and some computer generated data containing deliberately introduced sampling error are analyzed. (RC)

The Pearson correlation is used to depict effect sizes in the context of item response theory. Amultidimensional Rasch model is used to directly estimate the correlation between latent traits. Monte Carlo simulations were conducted to investigate whether the population correlation could be accurately estimated and whether the bootstrap method…