This is a methodological critique of research by the Best Practice in Grouping Students (BPGS) project claiming teacher bias in allocating students to first-year secondary school mathematics teaching sets ("British Educational Research Journal," 45(4), 873-897 [EJ1223692]). The research assumes that bias could be shown by non-random…

As with any psychometric models, the validity of inferences from cognitive diagnosis models (CDMs) determines the extent to which these models can be useful. For inferences from CDMs to be valid, it is crucial that the fit of the model to the data is ascertained. Based on a simulation study, this study investigated the sensitivity of various fit…

Class size reduction policies have been widely implemented around the world in recent years. However, findings about the effects of class size on student achievement have been mixed. This study examines class size effects on fourth-grade mathematics achievement in 14 European countries using data from TIMSS (Trends in International Mathematics and…

Assessing fit of psychometric models has always been an issue of enormous interest, but there exists no unanimously agreed upon item fit diagnostic for the models. Bayesian networks, frequently used in educational assessments (see, for example, Mislevy, Almond, Yan, & Steinberg, 2001) primarily for learning about students' knowledge and…