Item response theory (IRT) is having a major impact on the field of testing. This special issue presents an introduction and seven papers concerning developments in IRT applications. Some important IRT research being conducted outside the United States is highlighted. (SLD)

Multidimensional adaptive testing (MAT) procedures are proposed for the measurement of several latent traits by a single examination. Bayesian latent trait estimation and adaptive item selection are derived. Simulations were conducted to compare the measurement efficiency of MAT with those of unidimensional adaptive testing and random…

This study investigated the adequacy of the Rasch model in equating existing standardized tests with groups of examinees not widely separated in ability. With the exception of one test pair and one grade level, the Rasch model using the anchor test procedure provided a reasonably satisfactory means of equating. (Author/CTM)

Multidimensional item response theory (IRT) models have been proposed for better understanding the dimensional structure of data or to define diagnostic profiles of student learning. A compensatory multidimensional two-parameter partial credit model (M-2PPC) for constructed-response items is presented that is a generalization of those proposed to…