The results of this study suggest that for purposes of estimating ability by latent trait methods, the Rasch model compares favorably with the three-parameter logistic model. Using estimated parameters to make predictions about 25 actual number-correct score distributions with samples of 1,000 cases each, those predicted by the Rasch model fit the…

The purpose of this study was to determine whether option weighting improved the internal consistency and intercorrelation of the subtests. The differential option-weighting scheme employed in this study is based on one devised by Guttman. The tests were first scored with Guttman-type weights and then with conventional correction-for-guessing…