Measurement invariance is crucial for an effective and valid measure of a construct. Invariance holds when the latent trait varies consistently across subgroups; in other words, the mean differences among subgroups are only due to true latent ability differences. Differential item functioning (DIF) occurs when measurement invariance is violated.…

This study serves as a teaching aid for teachers of introductory statistics. The aim of this study was limited to determining various sample sizes when estimating population proportion. Tables on sample sizes were generated using a C[superscript ++] program, which depends on population size, degree of precision or error level, and confidence…

Correlational analyses are one of the most popular quantitative methods, yet also one of the mostly frequently misused methods in social and behavioral research, especially when analyzing ordinal data from Likert or other rating scales. Although several correlational analysis options have been developed for ordinal data, there seems to be a lack…

This "Research Commentary" addresses the quality of statistical research in mathematics education. To do so, 10 years of Journal for Research in Mathematics Education (JRME) articles were analyzed on the basis of criteria suggested by the American Educational Research Association, American Psychological Association, and National Council for…

This paper presents key new developments in the THES - QS World University Rankings in 2007, related to enhancements to the "Peer Review", "Data Collection" and "Statistical Aggregation" utilised in this ranking as well as discussing the decision to utilise Full-Time Equivalent (FTE) figures for personnel statistics. Indicator correlation is also…

In educational effectiveness research, multilevel data analyses are often used because research units (most frequently, pupils or teachers) are studied that are nested in groups (schools and classes). This hierarchical data structure complicates designing the study because the structure has to be taken into account when approximating the accuracy…

The National Student Survey (NSS) of course experience satisfaction is sent to final year students of all higher education institutions in England, Northern Ireland, Scotland and Wales (N = 171,290 and 157,342 students in 2005 and 2006) and results are made publicly available. The present investigation assesses the reliability and appropriate use…

Research in fields other than education has found that studies with small sample sizes tend to have larger effect sizes than those with large samples. This article examines the relationship between sample size and effect size in education. It analyzes data from 185 studies of elementary and secondary mathematics programs that met the standards of…

A multidimensional item response theory model that accounts for response style factors is presented. The model, a multidimensional extension of Bock's nominal response model, is shown to allow for the study and control of response style effects in ordered rating scale data so as to reduce bias in measurement of the intended trait. In the current…

Quality measurement is essential in every form of research, including institutional research and assessment. Unfortunately, most survey research today (both published and unpublished) is lacking with regards to quality measurement. Reporting means and standard deviations based on ordinal measures is an inappropriate, yet widespread practice in the…

Instability in the school population between school entrance and school leaving is not "just a problem of missing data" but often the visible result of the educational problems in some schools and is, therefore, not merely to be treated as missing data but as indicator for the quality of educational processes. Even the most superior…

Good quality data is paramount for applied economic research. If the data are distorted, corresponding conclusions may be incorrect. We demonstrate how Benford's law, the distribution that first digits of numbers in certain data sets should follow, can be used to test for data abnormalities. We conduct an analysis of nine commonly used data sets…

In meta-analysis, it is common to have dependent effect sizes, such as several effect sizes from the same sample but measured at different times. Cheung and Chan proposed the adjusted-individual and adjusted-weighted procedures to estimate the degree of dependence and incorporate this estimate in the meta-analysis. The present study extends the…

Statistical neighbour models provide one method for benchmarking progress. For each local authority (LA), these models designate a number of other LAs deemed to have similar characteristics. These designated LAs are known as statistical neighbours. Any LA may compare its performance (as measured by various indicators) against its statistical…

THE RESULTS OF THIS STUDY CLEARLY INDICATE THE INADVISABILITY OF ATTEMPTING TO PERFORM ITEM ANALYSES BASED UPON SMALL SAMPLES. THE SINGLE ITEM DISCRIMINATION INDEX BASED UPON SAMPLES OF SIZE 15, 30, OR 60, HAS LITTLE OR NO VALUE. THOSE BASED UPON SAMPLES OF 120 ARE ONLY INDICATIVE IN NATURE. (LP)