The observed probability "p" is the social scientist's primary tool for evaluating the outcome of statistical hypothesis tests. The small-sample accuracy of nonnull asymptotic distributions of several functions of "p" was studied. Implications for use of the approximations are discussed. (SLD)

Modifications are proposed to the recently developed method of comparing one-step M-estimators of location corresponding to two independent groups that provides good control over the probability of Type I error even for unequal sample size, unequal variances, and different shaped distributions. Simulation results reveal cautions required. (SLD)

Presents a critique of published learner control studies that highlights problems with definitions of learner control, theoretical foundations, treatment duration, outcome measures, sample sizes, and conclusions. Recommendations are made concerning the exploration of alternative models for research focused on learner control and other aspects of…

The extent to which log-linear smoothing could improve the accuracy of common-item equating by the chained equipercentile method in small samples of examinees was investigated with responses from a 100-item test and 93,283 examinees. Smoothing reduced the sample size required for a given degree of accuracy. (SLD)

One-parameter and three-parameter item response theory (IRT) model estimates were compared with estimates obtained from two modified one-parameter models that incorporated a constant nonzero guessing parameter. Using small-sample simulation data (50, 100, and 200 simulated examinees), modified 1-parameter models were most effective in estimating…

Describes a study that investigated the relationship between article citedness and journal impact based on publication lists of 16 Norwegian scientists. Highlights include cohortization; correlation between article citedness and journal impact for uncohortized material; effect of article sample size; and differences in journal choice between…

Power and Type I error rates were estimated for contingency tables with small sample sizes for the following four types of tests: (1) Pearson's chi-square; (2) chi-square with Yates's continuity correction; (3) the likelihood ratio test; and (4) Fisher's Exact Test. Various marginal distributions, sample sizes, and effect sizes were examined. (SLD)

Empirical studies demonstrated Type-I error (TIE) inflation (especially for highly discriminating easy items) of the Mantel-Haenszel chi-square test for differential item functioning (DIF), when data conformed to item response theory (IRT) models more complex than Rasch, and when IRT proficiency distributions differed only in means. However, no…

The standard Pearson correlation coefficient is a biased estimator of the true population correlation, ?, when the predictor and the criterion are range restricted. To correct the bias, the correlation corrected for range restriction, r-sub(c), has been recommended, and a standard formula based on asymptotic results for estimating its standard…

Repeated measures and longitudinal studies arise often in social and behavioral science research. During the planning stage of such studies, the calculations of sample size are of particular interest to the investigators and should be an integral part of the research projects. In this article, we consider the power and sample size calculations for…

Whether hierarchical logistic regression can reduce the sample size requirement for estimating optimal cutoff scores in a course placement service where predictive validity is measured by a threshold utility function is explored. Data from courses with varying class size were randomly partitioned into two halves per course. Nonhierarchical and…

A confirmatory factor analysis was conducted on the Wechsler Intelligence Scale for Children-Third Edition (WISC-III; D. Wechsler, 1991) with a sample of 579 Australian children referred for assessment because of academic difficulties in the classroom. The children were administered the WISC-III as part of the initial eligibility determination…

Grade retention is an intervention that has received increasing scrutiny as policies, practices, and results of research diverge. This longitudinal study examines the reading growth trajectories of students (n=147) from first-through eighth-grade. Hierarchical Linear Modeling (HLM) analytic procedures provide unique insights regarding the relative…

Authors examined attitudes towards diversity among college students who participated in a civic type living-learning program. The purpose of this longitudinal study was to examine the differences in students in a civic type living-learning program and a comparison group in undergraduate student understanding and appreciation of diversity. A…

Background. A variety of research designs have been employed to explore the efficacy of the wide range of interventions for sex offenders with learning disabilities. This paper reviews these studies to consider the efficacy of such treatments. Methods. Computerized searches and less formal literature gathering led to the identification of 31…