The use of analysis of variance (ANOVA), multivariate analysis of variance (MANOVA), and analysis of covariance (ANCOVA) by educational researchers was studied through review of several prominent research journals. The analyses suggest that researchers rarely verify that validity assumptions are satisfied, and typically use analyses that are…

Colleagues in the field of mental health have made considerable progress developing inventories of evidence-based practice; however, the field of special education for children with emotional or behavioral disorders has only recently begun to do so. This paper provides some personal reflections on four major issues for consideration as we pursue…

This summary presents the main findings from a data mapping and analysis study commissioned by the Local Government Association (LGA) from the National Foundation for Educational Research (NFER) as part of a two-year development and research programme, Narrowing the Gap. This programme seeks to make a significant difference in "narrowing the…

The present study investigates whether the Early Development Instrument (Offord & Janus, 1999) measures school readiness similarly across different groups of children. We employ ordinal logistic regression to investigate differential item functioning, a method of examining measurement bias. For 40,000 children, our analysis compares groups…

In educational research, nonessential factors are commonly ignored and when accounted for, they are often treated statistically as fixed effects. Yet many researchers in these situations generalize their findings beyond the specific levels selected; however, the analyses may require treating the factor as a random effect. Such inappropriate…

Some item response theory (IRT) techniques work in applications even though the usual structural IRT assumptions, and local independence (LI) in particular, do not hold. When the departure from LI is too great, traditional procedures will break down. Although violations of strictly unidimensional, monotone, locally independent latent structure can…

Concern over the validity of statistical tests performed on data that may not satisfy underlying assumptions has prompted methodological researchers to perform Monte Carlo studies for frequently used tests. Unfortunately, these studies appear to have had little impact on methodological practice. One reason is the lack of an overarching framework…

The Random Normal Scores Test (RNST) has been suggested as a powerful alternative to the use of the parametric analysis of variance (ANOVA) test when the underlying population is non-normally distributed. The major support for this suggestion rests on asymptotic theory. An empirical analysis of the RNST performed under the F and Chi-square…

More than ever, educators are expected to make decisions that guarantee quality instruction. As knowledge emerges, so do philosophies, opinions, and rhetoric about definitions of instructional excellence. From policy makers to classroom teachers, educators need ways to separate misinformation from genuine knowledge and to distinguish scientific…

Comparing variability of test scores across alternate forms, test conditions, or subpopulations is a fundamental problem in psychometrics. A confidence interval for a ratio of standard deviations is proposed that performs as well as the classic method with normal distributions and performs dramatically better with nonnormal distributions. A simple…

In their book, IQ and the Wealth of Nations, Lynn and Vanhanen ([Lynn, R. and Vanhanen, T. (2002). IQ and the wealth of nations. Westport, CT: Praeger.]) proposed the hypothesis that "the intelligence of the populations has been a major factor responsible for the national differences in economic growth and for the gap in per capita income between…

Since university enrollment forecasting is very important, many different methods and models have been proposed by researchers. Two new methods for enrollment forecasting are introduced: (1) the fuzzy time series model; and (2) the artificial neural networks model. Fuzzy time series has been proposed to deal with forecasting problems within a…

A method is proposed for sequential evaluation of reliability of psychometric instruments. Sample size is unfixed; a test statistic is computed after each person is sampled and a decision is made in each stage of the sampling process. Results from a series of Monte-Carlo experiments establish the method's efficiency. (SLD)

The article examines the concepts of power and control in research design and applies them to a review of the validity of three studies (EC 600 064-066) evaluating the effectiveness of using Irlen tinted lenses with reading-disabled persons. Internal validity, external validity, statistical conclusion validity, and construct validity are…

Techniques for adjusting census figures are discussed, with a focus on sampling error, uncertainty of estimates resulting from the luck of sample choice. Computer simulations illustrate the ways in which the smoothing algorithm may make adjustments less, rather than more, accurate. (SLD)