Item response theory (IRT) is based on the assumption that a direct relationship exists between an examinee's total performance on a set of items and the difficulty of each item on the test. The Rasch model represents this relationship mathematically on an equal interval scale. This paper argues that IRT, under the required conditions, provides…

A study of the context effects on item parameters for one- and three-parameter latent trait models showed that: (1) changes in context affected their item difficulties; and (2) context effects were more important in making predictions for single items than for groups of items. (Author/RL)

Research on the Rasch model of test and item analysis was applied to tests constructed from item banks for reading and mathematics with respect to five practical problems for scaling items and equating test forms. The questions were: (1) Does the Rasch model yield the same scale value regardless of the student sample? (2) How many students are…

Two procedures are presented for detecting violations of the unidimensionality assumption made by latent trait models without requiring factor analysis of inter-item correlation matrices. Both procedures require that departures from unidimensionality be hypothesized beforehand. This is usually possible in achievement tests where several content…

The development of the emerging technology of item writing was motivated in part by the desire to reduce potential subjectivity and bias between different item writers who attempt to construct parallel achievement tests. The present study contrasts four test forms constructed by the combined efforts of six item writers using four methods of item…

Studies carried out over a 12-year period addressed fundamental questions on the use of Rasch-based item banks. Large field tests administered in grades 3-8 of reading, mathematics, and science items, as well as standardized test results were used to explore the possible effects of many factors on item calibrations. In general, the results…

This paper argues that no single measurement strategy serves all purposes and that applying methods and techniques which allow a variety of data elements to be retrieved and juxtaposed may be an investment in the future. Item response theory, Rasch model, and latent trait theory are all approaches to a single conceptual topic. An abbreviated look…

Greater knowledge about the practical application of Rasch technology can help in avoiding misapplications and confusions in testing programs. Equal interval curriculum-based scaling makes possible the following improvements in measuring basic skills achievement by enabling testing programs to: (1) individualize the difficulty level of…

A collection of 96 mathematics items are presented for state and local education agencies to draw upon in designing their own minimal competency tests. These items, part of the National Assessment of Educational Progress, have been reviewed in terms of their appropriateness for a minimal competency test for high school graduation. The items are…