Educational researchers commonly use the rule of thumb of "design effect smaller than 2" as the justification of not accounting for the multilevel or clustered structure in their data. The rule, however, has not yet been systematically studied in previous research. In the present study, we generated data from three different models…

Many assessment and evaluation studies use statistical hypothesis tests, such as the independent samples t test or analysis of variance, to test the equality of two or more means for gender, age groups, cultures or language group comparisons. In addition, some, but far fewer, studies compare variability across these same groups or research…

This Monte Carlo simulation study investigated methods of forming product indicators for the unconstrained approach for latent variable interaction estimation when the exogenous factors are measured by large and unequal numbers of indicators. Product indicators were created based on multiplying parcels of the larger scale by indicators of the…

There is extensive research on the benefits of making data-informed decisions to improve learning, but these benefits rely on the data being effectively interpreted. Despite educators' above-average intellect and education levels, there is evidence many educators routinely misinterpret student data. Data analysis problems persist even at districts…

We propose a new limited-information goodness of fit test statistic C[subscript 2] for ordinal IRT models. The construction of the new statistic lies formally between the M[subscript 2] statistic of Maydeu-Olivares and Joe (2006), which utilizes first and second order marginal probabilities, and the M*[subscript 2] statistic of Cai and Hansen…

Equating functions are supposed to be population invariant, meaning that the choice of subpopulation used to compute the equating function should not matter. The extent to which equating functions are population invariant is typically assessed in terms of practical difference criteria that do not account for equating functions' sampling…

Across many areas of psychology, concordance is commonly used to measure the (intragroup) agreement in ranking a number of items by a group of judges. Sometimes, however, the judges come from multiple groups, and in those situations, the interest is to measure the concordance between groups, under the assumption that there is some within-group…

Written by a social worker for social work students, this is a nuts and bolts guide to statistics that presents complex calculations and concepts in clear, easy-to-understand language. It includes numerous examples, data sets, and issues that students will encounter in social work practice. The first section introduces basic concepts and terms to…

Demonstrating good reliability for the difference score in measurement, the results of this study indicate that the difference score is often highly reliable when the correlation between true change and true initial status is nonnegative. In general, when individual differences in true change are appreciable, the difference score shows strong…

In a meta-analysis of the effect of adding hypnosis to cognitive-behavioral treatments for weight reduction, additional data were obtained from authors of two previous studies, and computational inaccuracies in the previous meta-analyses were corrected. Discusses findings. Correlational analyses indicated that the benefits of hypnosis increased…

School-effectiveness research has not yet been able to identify the factors of effective and noneffective schools, the real contribution of the significant factors, the true sizes of school effects, and the generalizability of school-effectiveness results. This paper presents findings of a meta analysis, the Dutch PSO programme, that was used to…

A meta-analysis for six weight-loss studies comparing the efficacy of cognitive-behavior therapy (CBT) alone to CBT plus hypnotherapy. Notes that "the addition of hypnosis substantially enhanced treatment outcome." Concludes that the addition of hypnosis to CBT for weight loss results in, at most, a small enhancement of treatment…

This guide is designed to assist those readers of "The Condition of Education" and similar reports who may lack experience or confidence in reading and understanding statistical information. It serves four purposes (1) identifies and describes the principal features of statistical tables and charts; (2) presents a few illustrations of…

Outlines the simple exercise of measuring the length of an object as a concrete paradigm of the entire process of making chemical measurements and treating the resulting data. Discusses the procedure, significant figures, measurement error, spurious data, rejection of results, precision and accuracy, and student responses. (TW)

The National Education Longitudinal Study of 1988 (NELS:88) is a large-scale, national longitudinal study designed and sponsored by the National Center for Education Statistics (NCES), with support from other government agencies. Beginning in the spring of 1988 with a cohort of eighth graders (25,000) attending public and private schools across…