To ensure test security and fairness, alternative forms of the same test are administered in practice. However, alternative forms of the same test generally do not have the same test difficulty level, even though alternative test forms are designed to be as parallel as possible. Equating adjusts for differences in difficulties among forms of the test. Six traditional equating methods are consid...

CONTEXT Item response theory (IRT) measurement models are discussed in the context of their potential usefulness in various medical education settings such as assessment of achievement and evaluation of clinical performance. PURPOSE The purpose of this article is to compare and contrast IRT measurement with the more familiar classical measurement theory (CMT) and to explore the benefits of IR...

In equating, when common items are internal and scoring is in terms of the number of correct items, some pairs of total scores (X) and common-item scores (V ) can never be observed in a bivariate distribution of X and V ; these pairs are called structural zeros (Bishop, Fienberg, & Holland, 2007; Holland & Wang, 1987). This study examines how different approaches to handling structural zeros gi...

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Since the IEA's Third International Mathematics and Science Study, one of the major objectives of international surveys in education has been to report trends in achievement. The names of the two current IEA surveys reflect this growing interest: Trends in International Mathematics and Science Study (TIMSS) and Progress in International Reading Literacy Study (PIRLS). Similarly a central concer...