The growing number of children in primary schools in Germany who have German as their second language (L2) has raised questions about the fairness of performance assessment. Fair tests are a prerequisite for distinguishing between L2 learning delay and a specific learning disability. We evaluated five commonly used reading and spelling tests for…

Traditional psychometric guidelines suggest that at least several hundred respondents are needed to obtain accurate parameter estimates under the Rasch model. However, recent research indicates that Rasch equating results in accurate parameter estimates with sample sizes as small as 25. Item parameter drift under the Rasch model has been…

In common-item equating the anchor block is generally built to represent a miniature form of the total test in terms of content and statistical specifications. The statistical properties frequently reflect equal mean and spread of item difficulty. Sinharay and Holland (2007) suggested that the requirement for equal spread of difficulty may be too…

The psychometric properties and multigroup measurement invariance of scores across subgroups, items, and persons on the "Reading for Meaning" items from the Georgia Criterion Referenced Competency Test (CRCT) were assessed in a sample of 778 seventh-grade students. Specifically, we sought to determine the extent to which score-based…

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.…