For many reasons, students do not always perform on tests in ways that are congruent with their true abilities or achievement levels. Problems of this sort may be especially common on Title I evaluations where the tests administered are too difficult for a large percentage of the students. Such considerations raise the questions of whether…

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…