The four-parameter logistic (4PL) Item Response Theory (IRT) model has recently been reconsidered in the literature due to the advances in the statistical modeling software and the recent developments in the estimation of the 4PL IRT model parameters. The current simulation study evaluated the performance of expectation-maximization (EM),…

The effects of extended time on the writing performance of university students with learning disabilities (LD) was examined. Thirty-eight students (19 LD; 19 non-LD) completed a collection of cognitive, linguistic, and literacy measures, and wrote essays under regular and extended time conditions. Limited evidence was found to support the…

This simulation study compared the performances (Type I error and power) of Mantel-Haenszel (MH), SIBTEST, and item response theory-likelihood ratio (IRT-LR) methods under certain conditions. Manipulated factors were sample size, ability differences between groups, test length, the percentage of differential item functioning (DIF), and underlying…

For this dissertation, four item purification procedures were implemented onto the generalized linear mixed model for differential item functioning (DIF) analysis, and the performance of these item purification procedures was investigated through a series of simulations. Among the four procedures, forward and generalized linear mixed model (GLMM)…

DETECT is a nonparametric methodology to identify the dimensional structure underlying test data. The associated DETECT index, "D[subscript max]," denotes the degree of multidimensionality in data. Conditional covariances (CCOV) are the building blocks of this index. In specifying population CCOVs, the latent test composite [theta][subscript TT]…

This study elaborates the Rasch differential item functioning (DIF) model formulation under the marginal maximum likelihood estimation context. Also, the Rasch DIF model performance was examined and compared with the Mantel-Haenszel (MH) procedure in small sample and short test length conditions through simulations. The theoretically known…

Three decision consistency and accuracy (DC/DA) methods, the Livingston and Lewis (LL) method, LEE method, and the Hambleton and Han (HH) method, were evaluated. The purposes of the study were: (1) to evaluate the accuracy and robustness of these methods, especially when their assumptions were not well satisfied, (2) to investigate the "true"…

This study explored the effects of external anchor test length on final equating results of several equating methods, including equipercentile (frequency estimation), chained equipercentile, kernel equating (KE) poststratification PSE with optimal bandwidths, and KE PSE linear (large bandwidths) when using the nonequivalent groups anchor test…

Traditionally, the fixed-length linear paper-and-pencil (P&P) mode of administration has been the standard method of test delivery. With the advancement of technology, however, the popularity of administering tests using adaptive methods like computerized adaptive testing (CAT) and multistage testing (MST) has grown in the field of measurement…

Many of the currently available statistical indexes to detect answer copying lack sufficient power at small [alpha] levels or when the amount of copying is relatively small. Furthermore, there is no one index that is uniformly best. Depending on the type or amount of copying, certain indexes are better than others. The purpose of this article was…

A study was conducted to compare, with simulated unidimensional and two-dimensional sets, the Type I error probabilities and rejection rates obtained with two versions of the LISREL computer program, the earlier version PRELIS/LISREL 7 and the later version PRELIS2/LISREL8, a version that corrects the asymptotic covariance matrix. Unidimensional…

Alternative mathematical models for scoring and decision making with criterion referenced tests are described, especially as they concern appropriate test length and methods of establishing statistically valid cutting scores. Several of these approaches are reviewed and compared on formal-analytic and empirical grounds: (1) Block's approach to…

An adaptive testing strategy is described for achievement tests covering multiple content areas. The strategy combines adaptive item selection both within and between the subtests in the multiple-subtest battery. A real-data simulation was conducted to compare the results from adaptive testing and from conventional testing, in terms of test…

A study investigated the validity of an English listening skills test by comparing the results of native American and British English speakers with those of Dutch students of English as a second language. A hypothesis suggested that two-thirds of the items would test listening skills and the remaining third would test other knowledge. Test results…

This study evaluated whether the addition of a writing section to the SAT Reasoning Test™ (referred to as the SAT® in this study) would impact test-taker performance because of fatigue caused by increased test length. The study also investigated test-takers' subjective feelings of fatigue. Ninety-seven test-takers were randomly assigned to three…