Browsing by Author "Boss, Marvin W."
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Item The effect of test length and IRT model on the distribution and stability of three appropriateness indexes(1992) Noonan, Brian W.; Boss, Marvin W.; Gessaroli, Marc E.The extent to which three appropriateness indexes-Z, ECIZ₄, and W (a variation of Wright’s person-fit statistic)-are well-standardized was investigated in a monte carlo study. To assess the effects of the item response theory (IRT.) model and test length on the distribution of the indexes and their cutoff values at three false positive rates, nonaberrant response patterns were generated. ECIZ₄ most closely approximated a normal distribution, showing less skewness and kurtosis than Z, and W. The ECIZ₄ cutoff values were affected less by test length and the IRT model than were Z, and W. In contrast, the distribution of W was the least stable over replications, and its cutoff values varied greatly depending on the IRT model and test length. Index terms: appropriateness measurement, caution index, item response theory (person fit), person-fit statistics, unusual response patterns.Item The effects on parameter estimation of correlated dimensions and a distribution-restricted trait in a multidimensional item response model(1993) Batley, Batley; Boss, Marvin W.This study was designed to assess the effects on parameter estimation of correlated dimensions and a distribution-restricted trait on one dimension using a two-dimensional item response theory model. Multidimensional analysis of simulated two-dimensional item response data fitting a multidimensional two-parameter logistic item response theory model (McKinley & Reckase, 1983a; Reckase & McKinley, 1991) was done using the program MIRTE (Carlson, 1987). Six datasets (2 trait distributions x 3 levels of correlation between dimensions) of 2,000 trait vectors over 104 items were generated. Each dataset was analyzed and replicated 100 times. Trait and item parameters generally were recovered adequately in the datasets in which both traits were normally distributed over the full range. In the datasets with a restricted range of trait level on the second dimension, recovery of the trait and item parameters was affected adversely. The results indicated that MIRTE recovers the structure of a multidimensional correlated space better than reported in earlier studies, especially when items are multidimensional. Index terms: correlated traits, multidimensional item parameter estimates, multidimensional item response theory, multidimensional trait estimates, restricted traits.