Mixture item response theory (IRT) models aid the interpretation of response behavior on personality tests and may provide possibilities for improving prediction. Heterogeneity in the population is modeled by identifying homogeneous subgroups that conform to different measurement models. In this study, mixture IRT models were applied to the…

Criteria had been proposed for assessing the severity of possible test security violations for computerized tests with high-stakes outcomes. However, these criteria resulted from theoretical derivations that assumed uniformly randomized item selection. This study investigated potential damage caused by organized item theft in computerized adaptive…

The objective of this study is to explore the potential for developing IRT-based working memory scales for assessing specific working memory components in children (8-13 years). These working memory scales should measure cognitive abilities reliably in the upper range of ability distribution as well as in the normal range, and provide a…

Minimal research has been conducted contrasting the effectiveness of various testing accommodations for college students diagnosed with ADHD. The current assumption is that these students are best served by extending the time they have to take a test. It is the supposition of these investigators that paced item presentation may be a more…

Various taxonomies of Raven's Advanced Progressive Matrices (APM) items have been proposed in the literature to account for performance on the test. In the present article, three such taxonomies based on information processing, namely Carpenter, Just and Shell's [Carpenter, P.A., Just, M.A., & Shell, P., (1990). What one intelligence test…

Recent advances in educational technologies and the wide-spread use of computers in schools have fueled innovations in test construction and analysis. As the measurement accuracy of a test depends on the quality of the items it includes, item selection procedures play a central role in this process. Mathematical programming and the item response…

U.S. state educational testing programs administer tests to track student progress and hold schools accountable for educational outcomes. Methods from item response theory, especially Rasch models, are usually used to equate different forms of a test. The most popular method for estimating Rasch models yields inconsistent estimates and relies on…

Cognitive diagnostic models (CDMs) model the probability of correctly answering an item as a function of an examinee's attribute mastery pattern. Because estimation of the mastery pattern involves more than a continuous measure of ability, reliability concepts introduced by classical test theory and item response theory do not apply. The cognitive…

This study investigates the effect of reporting the unadjusted raw scores in a high-stakes language exam when raters differ significantly in severity and self-selected questions differ significantly in difficulty. More sophisticated models, introducing meaningful facets and parameters, are successively used to investigate the characteristics of…

Type I error rates of the likelihood ratio test for the detection of differential item functioning (DIF) in the partial credit model were investigated using simulated data. The partial credit model with four ordered performance levels was used to generate data sets of a 30-item test for samples of 300 and 1,000 simulated examinees. Three different…

An alternative method of finding a common metric for separate calibrations through the use of a common (anchor) set of items is presented. Based on Raju's (1988) method of calculating the area between the two item response functions, this (area-minimization) method minimizes the sum of the squared exact unsigned areas of each of the common items.…

This study provided preliminary results about the performance of the DIMTEST statistical procedure for detecting multidimensionality with data simulated from both compensatory and noncompensatory models under a latent structure where all items in a test were influenced by the same two abilities. For the first case, data were simulated to reflect…

Considers tests of unidimensionality in polytomous Rasch models against a specified alternative, given by a partition of the items into subgroups, that are believed to measure different dimensions of the latent construct. Uses data from an occupational health study to motivate and illustrate the methods. (SLD)

Studied the evidence for the practice of using parcels of item as manifest variables in structural equation modeling procedures. Findings suggest that the unconsidered use of parcels is never warranted, but the considered use of parcels cannot be dismissed out of hand. Describes a number of parceling techniques and their strengths and weaknesses.…

Provides a general method that adjusts for the inflation of information associated with a test containing item clusters and a computational scheme for the evaluation of the factors of adjustment for clusters in the restrictive and general cases. Illustrates the approach with an analysis of National Assessment of Educational Progress data. (SLD)