For educational achievement tests that employ multiple-choice (MC) items and aim to reliably classify students into performance categories, it is critical to design MC items that are capable of discriminating student performance according to the stated achievement levels. This is accomplished, in part, by clearly understanding how item design…

This article discusses the assumptions required by the item response theory (IRT) true-score equating method (with Stocking & Lord, 1983; scaling approach), which is commonly used in the nonequivalent groups with an anchor data-collection design. More precisely, this article investigates the assumptions made at each step by the IRT approach to…

National Assessment is a data gathering project designed to provide information, in ten subject areas, about knowledge, skills, understandings and attitudes of young people in this country, and to assess changes in these variables over time. The data is collected and reported at the item level. Each exercise was developed with emphasis on content…