Standard procedures for estimating item parameters in Item Response Theory models make no use of auxiliary information about test items, such as their format or content, or the skills they require for solution. This paper describes a framework for exploiting this information, thereby enhancing the precision and stability of item parameter…

The extent, causes, and importance of context effects on item parameters for one- and three-parameter latent-trait models were examined. Items were taken from the California Achievement Tests Reading Comprehension and Mathematics Concepts and Applications subtests. The reading items were administered to 1,678 fourth-grade students, and the…