Developed a method for conditional pairwise estimation in the Rasch model for ordered response categories using principal components analysis and evaluated the procedure through a simulation study. Results show that the quality of the estimates is excellent. (SLD)

Attempted to illuminate practical limitations on the Rasch model by focusing on the recovery of the density scale through five simulation trials. Results show that when error distributions are insufficient, the results may be ordinal at best, and when error distributions are nonsymmetrical, the positions of items may be biased with respect to the…

Studied four different approaches for handling missing data for their capacity to mitigate against the effect of omitted responses on person location estimation. Results from a Monte Carlo study show that the hot-decking procedure performed best of the methods examined. (SLD)

Examined the effectiveness of the Sympson-Hetter technique and rotated content balancing relative to no exposure control and no content rotation conditions in a computerized adaptive testing system based on the partial credit model. Simulation results show the Sympson-Hetter technique can be used with minimal impact on measurement precision,…

Presents empirically based item selection guidelines for moving the cut score on equated tests consisting of "n" dichotomous items calibrated assuming the Rasch model. Derivations of lemmas that underlie the guidelines are provided as well as a simulated example. (SLD)

Used Monte Carlo simulation to determine the psychometric conditions under which differences between raw scores and Rasch transformations of those raw scores are detectable through two-way analysis of variance. Findings demonstrate the inherent inadequacy of untransformed raw scores for two-way analysis of variance. (SLD)

Describes a class of rater effects, differential rater functioning over time (DRIFT), that depicts rater-by-time interactions. Also describes Rasch measurement procedures designed to identify these types of DRIFT in rating data. Applied these procedures to simulated data to show their usefulness in classifying raters as aberrant or non-aberrant…

Used Monte Carlo simulation to compare the relative measurement efficiency of polytomous modeling and dichotomous modeling under different scoring schemes and termination criteria. Results suggest that polytomous computerized adaptive testing (CAT) yields marginal gains over dichotomous CAT when termination criteria are more stringent. Discusses…

Proposes a factorial procedure for investigating differential distractor functioning in multiple choice items that models each distractor with a distinct distractibility parameter. Results of a simulation study show that the parameters of the proposed modeling were recovered very well. Analysis of 10 4-choice items from a college entrance…

Studied five factors that can affect the equating of scores from two tests onto a common score scale through the simulation and equating of 4,860 item data sets. Findings indicate three statistically significant two-way interactions for common item length and test length, item difficulty standard deviation and item distribution type, and item…

Extended conventional two-group differential item function (DIF) analysis for dichotomous items to factorial DIF analysis for polytomous items where multiple grouping factors with multiple groups in each are analyzed jointly. Simulation studies and analysis of a real data set with 1,924 subjects show the parameters of the proposed modeling can be…