Presented and evaluated an adjusted Bonferroni method for controlling familywise rate when deleting parameters in specification addition searches. Simulation results show that the adjusted Bonferroni method controlled adequately for Type I errors in the initial addition stage of a two-stage search and with backward selection. (SLD)

Evaluated three types of multidimensional item response theory (MIRT) linking methods through two simulation studies. Results indicate that the best MIRT linking method was an unbiased, effective, and consistent estimator that produced accurate estimates of transformation parameters when errors in estimation of item parameters were manipulated…

Describes an idiosyncracy of the MULTILOG (D. Thissen, 1991) parameter estimation process discovered during a simulation study involving the graded response model. A misordering reflected in boundary function location parameter estimates resulted in a large negative contribution to the true score followed by a large positive contribution. These…

Relates Thurstonian models for paired comparisons data to Thurstonian models for ranking data and proposes an intermediate model for paired comparisons data that assigns nonzero probabilities to all transitive patterns and to some, but not all, intransitive patterns. Conducted a simulation study to investigate the performance of three alternative…

Developed a full maximum likelihood method for obtaining joint estimates of variances and correlations among continuous and polytomous variables with incomplete data that are missing at random with an ignorable missing mechanism. Simulation results and an empirical example illustrate the approach. (SLD)

Studied the effect of item parameter estimation for computation of linking coefficients for the test response function (TRF) linking/equating method. Simulation results showed that linking was more accurate when there was less error in the parameter estimates, and that 15 or 25 common items provided better results than 5 common items under both…

Presents a Bayesian method for obtaining an interval estimate of the population squared multiple correlation from an incomplete multivariate normal data set. Estimates were constructed using Gibbs sampling. Simulation studies indicate that the method can yield accurate interval estimates of the population squared multiple correlation. (SLD)

Presents and evaluates three estimators for "p," the proportion of success in predicting variable "Y," with nominal measurement, using predictor variables that also have nominal measurement. Showed through simulation that one estimator is always biased upward, and then proposed another possible estimator that involves using…

Considers the estimation of polynomial structural models and shows a limitation of an existing method. Introduces a new procedure, the generalized appended product indicator procedure, for nonlinear structural equation analysis. Addresses statistical issues associated with the procedure through simulation. (SLD)

Varied the number of items and categories per item to explore the effects on estimation of item parameters in the nominal response model. Simulation results show that increasing the number of items had little effect on item parameter recovery, but increasing the number of categories increased the error variance of the parameter estimates. (SLD)

Investigated the effect of item parameter drift on ability estimates under item response theory, simulating item response data for two testing occasions for the two-parameter logistic model under several crossed conditions. Results show that item parameter drift under the simulated conditions had a small effect on ability estimates. (SLD)

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)

Compared the quality of item parameter estimates for marginal maximum likelihood (MML) and Markov Chain Monte Carlo (MCMC) with the nominal response model using simulation. The quality of item parameter recovery was nearly identical for MML and MCMC, and both methods tended to produce good estimates. (SLD)

Investigated incorporating a testlet definition into the estimation of the conditional standard error of measurement (SEM) for tests composed of testlets using five conditional SEM estimation methods. Results from 3,876 tests from the Iowa Tests of Basic Skills and 1,000 simulated responses show that item-based methods provide lower conditional…

Nonlinear latent variable models are specified that include quadratic forms and interactions of latent regressor variable as special cases. To estimate the parameters, the models are put in a Bayesian framework with conjugate priors for the parameters. The proposed estimation methods are illustrated by two simulation studies. (SLD)