Drawing on recently developed methodology for structural equation modeling with categorical data, this article proposes a new approach for investigating the behavior of dichotomously scored test items in relation to other relevant (observed) variables. A linear structural model relates the latent ability variable to a set of observed scores.…

A method is proposed for equating different sets of items administered to different groups using the Rasch model. The Rasch equating model formulated describes one common Rasch scale in different groups with different but overlapping item sets. The model, based on the quasi-loglinear Rasch model, can be tested globally. (SLD)

A formal analysis is presented of the effects of item deletion on equating/scaling functions and reported score distributions. The phrase "item deletion" refers to the process of changing the original key of a flawed item to either all options correct, including omits, or to no options correct, i.e., not scoring the flawed item. There…

The purpose of this study was to compare the relative robustness of the one-, two-, and modified two-parameter latent trait logistic models for the Iowa Tests of Educational Development. Results suggest that the modified two-parameter model may provide the best representation of the data. (Author/BW)

The Preliminary Scholastic Aptitude Test/National Merit Scholarship Qualifying Test (PSAT/NMSQT) was equated to the Scholastic Aptitude Test (SAT) using item response theory (IRT) in a three-parameter logistic model. Estimated true formula score equating was used. Only the mathematical sections of the PSAT/NMSQT and SAT were used because the…

The work presented in this paper defined conceptually the concepts of multidimensional discrimination and information, derived mathematical expressions for the concepts for a particular multidimensional item response theory (IRT) model, and applied the concepts to actual test data. Multidimensional discrimination was defined as a function of the…

This study compared student performance on language-usage test items presented in two different formats: as discrete sentences and as items embedded in passages. American College Testing (ACT) Program's Assessment experimental units were constructed that presented 40 items in the two different formats. Results suggest item presentation may not…

The feasibility of pre-equating, or establishing conversions from raw to scaled scores through the use of pretest data before operationally administering a test, was investigated for the Scholastic Aptitude Test (SAT). Item-response theory based equating methods were used to estimate item parameters on SAT pretest data, instead of using final form…