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…

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…

Education statistics are rarely neutral; those who collect and analyze them have different purposes. In this article, Bracey discusses several principles of data interpretation to help educators avoid falling into statistical traps. For example, because such reports as A Nation At Risk contain many "selected, spun, distorted, and even manufactured…

Problems and procedures in assessing and obtaining fit of data to the Rasch model are treated and assumptions embodied in the Rasch model are made explicit. It is concluded that statistical tests are needed which are sensitive to deviations so that more than one item parameter would be needed for each item, and more than one person parameter would…

This study examined the influence of survey validity screening on the results from three group-administered school surveys administered to samples totaling approximately 5500 students in 19 schools. The estimated levels of risk behaviors, antisocial behaviors, and victim experiences were substantially reduced when respondents who gave multiple…