Often, important decisions regarding accountability and placement of students in performance categories are made on the basis of test scores generated from tests, therefore, it is important to evaluate the validity of the inferences derived from test results. One of the threats to the validity of such inferences is aberrant responding. Several…

Educational and psychological constructs are normally measured by multifaceted dimensions. The measured construct is defined and measured by a set of related subdomains. A bifactor model can accurately describe such data with both the measured construct and the related subdomains. However, a limitation of the bifactor model is the orthogonality…

In this article, we introduce a person-fit statistic called the hierarchy consistency index (HCI) to help detect misfitting item response vectors for tests developed and analyzed based on a cognitive model. The HCI ranges from -1.0 to 1.0, with values close to -1.0 indicating that students respond unexpectedly or differently from the responses…

When an examination consists in whole or part of constructed response test items, it is common practice to allow the examinee to choose a subset of the constructed response questions from a larger pool. It is sometimes argued that, if choice were not allowed, the limitations on domain coverage forced by the small number of items might unfairly…

Four factors essential to determining how many items should be constructed or sampled for a set of objectives are examined: (1) importance and type of decisions to be made with the results; (2) importance and emphases assigned to the instructional and behavioral objectives; (3) number of objectives; (4) practical constraints, such as item writing…