The technical complexities and sheer size of international large-scale assessment (LSA) databases often cause hesitation on the part of the applied researcher interested in analyzing them. Further, inappropriate choice or application of statistical methods is a common problem in applied research using these databases. This article serves as a…

This article illustrates the use of an explanatory item response modeling (EIRM) approach in the context of measuring group differences in science achievement. The distinction between item response models and EIRMs, recently elaborated by De Boeck and Wilson (2004), is presented within the statistical framework of generalized linear mixed models.…

The purpose of this Guide is to provide Mathematics and Science Partnership (MSP) project officials and evaluators with clear, practical advice on how to conduct rigorous evaluations of MSP projects at low cost. Specifically, this is a how-to Guide designed to enable MSP grantees and evaluators of MSP projects to answer questions about the…