The use of computers to build diagnostic inferences is presented in two contexts: (1) closed world, exemplified by the space shuttle launch monitoring system; and (2) open world, represented by computerized diagnostic testing of reading comprehension. The analysis shows that the closed world provides a substantially cleaner environment within…

Reports the results of several test-reliability experiments which compared a modified confidence weighted-admissible probability measurement (MCW-APM) with conventional forced choice or binary type (R-W) test scoring methods. Psychometric properties using G theory and conventional correlational methods are examined, and their implications for…

For many years personalization of achievement testing has been impossible in all but the simplest forms. Recently, item response theory (IRT), or latent trait theory, has emerged as a valuable tool which brings far greater flexibility to the process than had previously been possible. The single parameter Rasch Model, a mathematical model developed…

This report describes the development, operation, maintenance, and future prospects of the item banks pioneered by the Portland (Oregon) School District. At the time of this report, there were 3,500 mathematics, 2,200 reading, and 2,300 language usage items calibrated under the fixed parameter model of item response theory (IRT) for Grades 3-8.…