Studied the effects of sample size on the cumulative distribution of selected fit indices using Monte Carlo simulation. Generally, the comparative fit index exhibited very stable patterns and was less influenced by sample size or data types than were other fit indices. (SLD)

Describes a Windows program for checking the suitability of unidimensional logistic item response models for binary and ordered polytomous responses with respect to a given set of data. The program is based on predicting the observed test score distributions from the item characteristic curves. (SLD)

Illustrates a number of ways in which confidence intervals for reliability coefficients can be estimated. Suggests that authors who submit articles to "Educational and Psychological Measurement" report confidence intervals for reliability estimates whenever they report score reliabilities and that they note the interval estimation…

Considers a problem of simple random walks to study distributions of variances. Describes watching a drunk over a period of nights, taking a number of steps per night. Explores the full probability distribution for the variance of the data string and discusses the connection of the results to the problem of data binning. (Author/NB)

Since data in social and behavioral sciences are often hierarchically organized, special statistical procedures for covariance structure models have been developed to reflect such hierarchical structures. Most of these developments are based on a multivariate normality distribution assumption, which may not be realistic for practical data. It is…

The authors argue that a robust version of Cohen's effect size constructed by replacing population means with 20% trimmed means and the population standard deviation with the square root of a 20% Winsorized variance is a better measure of population separation than is Cohen's effect size. The authors investigated coverage probability for…

In Bayesian statistics, the choice of the prior distribution is often controversial. Different rules for selecting priors have been suggested in the literature, which, sometimes, produce priors that are difficult for the students to understand intuitively. In this article, we use a simple heuristic to illustrate to the students the rather…

Direct provision of public services can alter the balance of resources across income groups. We focus on the issues arising when taking account of the impact of publicly provided education services across the income distribution. We combine OECD information on spending per student in particular levels of the education system with micro data from…

This paper presents facts and figures of the international higher education. Facts reveal that the UK sells more brainpower per capita than anywhere else in the world. The UK has 1% of the world's population but undertakes 5% of the world's scientific research and produces 14% of the world's most highly cited papers (Universities UK 2010). More…

Confidence intervals (CIs) give information about replication, but many researchers have misconceptions about this information. One problem is that the percentage of future replication means captured by a particular CI varies markedly, depending on where in relation to the population mean that CI falls. The authors investigated the distribution of…

Distinguishing between discrete and continuous latent variable distributions has become increasingly important in numerous domains of behavioral science. Here, the authors explore an information-theoretic approach to latent distribution modeling, in which the ability of latent distribution models to represent statistical information in observed…

States in the U.S. are required to provide transition services to young people in special education to increase the likelihood of positive post-school outcomes (Individuals with Disabilities Education Act of 1990, IDEA, amended 1997). Fourteen years later the Individuals with Disabilities Education Improvement Act of 2004 strengthened transition…

The logic and uses of test equating are discussed, including three methods of test equating. The focus is on the conceptual underpinnings of each test equating method, rather than on the mathematics of the procedures. Additional consideration is given to the assumptions of each method and its respective strengths and weaknesses. A commonly…

Sampling error refers to variability that is unique to the sample. If the sample is the entire population, then there is no sampling error. A related point is that sampling error is a function of sample size, as a hypothetical example illustrates. As the sample statistics more and more closely approximate the population parameters, the sampling…

A new and unified approach to test equating is described that is based on log-linear models for smoothing score distributions and on the kernel method of nonparametric density estimation. The new method contains both linear and standard equipercentile methods as special cases and can handle several important equating data collection designs. An…