Investigates the equality of "p" correlated effect sizes for "k" independent studies in which treatment and control groups are compared using Hotelling's "T" statistic. Illustrates the procedure and discusses the importance of sample size. (SLD)

Examines education's effects on choice of medical care inputs and the subsequent relationship between these inputs and overall health. Specifically examines consumption of curative and preventive medical care and other lifestyle choices, using nultivariate analysis of three estimation models and 1987 National Medical Expenditure Survey data.…

Using data from the Longitudinal Study of American Youth (LSAY), the present study examined whether early acceleration of students into formal algebra at the beginning of middle school promoted evident growth in different mathematical areas (basic skills, algebra, geometry, and quantitative literacy) and stable growth across these mathematical…

Underpowered studies persist in the psychological literature. This article examines reasons for their persistence and the effects on efforts to create a cumulative science. The "curse of multiplicities" plays a central role in the presentation. Most psychologists realize that testing multiple hypotheses in a single study affects the Type I error…

Relations between self-concept and mental health are best understood from a multidimensional perspective. For responses by 903 adolescents (mean age = 12.6) to a new French translation of the Self Description Questionnaire II (SDQII), confirmatory factor analysis demonstrated a well-defined multidimensional factor structure of reliable, highly…

In this simulation study, we investigate the power and Type I error rate of a procedure based on the mean and covariance structure analysis (MACS) model in detecting differential item functioning (DIF) of graded response items with five response categories. The following factors were manipulated: type of DIF (uniform and non-uniform), DIF…

Structural equation modeling allows several methods of estimating the disattenuated association between 2 or more latent variables (i.e., the measurement model). In one common approach, measurement models are specified using item parcels as indicators of latent constructs. Item parcels versus original items are often used as indicators in these…

A sample of 37 children aged 4-7 years who all showed some autistic features was investigated. Children with a primary diagnosis of autism were compared with those diagnosed with a language disorder, on behaviours within four domains; social behaviour, imaginative activities, repetitive behaviour and communication. The aim was to identify…

Based on seminal work by Lord and Hambleton, Swaminathan, and Rogers, this article is an analytical, graphical, and conceptual reminder that item response theory (IRT) parameter invariance only holds for perfect model fit in multiple populations or across multiple conditions and is thus an ideal state. In practice, one attempts to quantify the…

Suppressor situations occur when the simultaneous inclusion of two predictors improves one or both validities. A common allegation is that suppressor effects rarely replicate and have little substantive import. We present substantive examples from two established research domains to counter this skepticism. In the first domain, we show how…

Mardia's measure of multivariate kurtosis has been implemented in many statistical packages commonly used by social scientists. It provides important information on whether a commonly used multivariate procedure is appropriate for inference. Many statistical packages also have options for missing data. However, there is no procedure for applying…

Using data on Moscow couples, this study investigates the division of household labor and its effects on marital conflict and thought of divorce. The hypotheses predict how spouses' economic resources, gender beliefs, and time constraints influence marital contention both directly and indirectly through wife's perceived division of household labor…

The most important things learned about violence and trauma in the past 20 years are that interpersonal violence is prevalent, with different forms co-occurring, and that victims' reactions are complex. Researchers are called to consider models that include the ecological context within which victims experience violence and trauma to gain a better…

In November 2004, economists Thomas Fuchs and Ludger Woessmann published a statistical analysis of the relationship between technology and student achievement using year 2000 data from the Programme for International Student Assessment (PISA). The 2000 PISA was the first in a series of triennial assessments of 15-year-olds conducted by the…

This manuscript introduces a new Bayesian finite mixture methodology for the joint clustering of row and column stimuli/objects associated with two-mode asymmetric proximity, dominance, or profile data. That is, common clusters are derived which partition both the row and column stimuli/objects simultaneously into the same derived set of clusters.…