A Monte Carlo simulation study was conducted to compare fit indices used for detecting the correct latent class in three dichotomous mixture item response theory (IRT) models. Ten indices were considered: Akaike's information criterion (AIC), the corrected AIC (AICc), Bayesian information criterion (BIC), consistent AIC (CAIC), Draper's…

Educational and psychological constructs are normally measured by multifaceted dimensions. The measured construct is defined and measured by a set of related subdomains. A bifactor model can accurately describe such data with both the measured construct and the related subdomains. However, a limitation of the bifactor model is the orthogonality…

Classically parallel, tau-equivalently parallel, and congenerically parallel models representing various degrees of part-test parallelism and their appropriateness for tests composed of multiple item formats are discussed. An appropriate reliability estimate for a test with multiple item formats is presented and illustrated. (SLD)

Addressing the shortcomings of classical item statistics for selecting criterion-referenced test items, this paper describes an optimal item selection procedure utilizing item response theory (IRT) and offers examples in which random selection and optimal item selection methods are compared. Theoretical advantages of optimal selection based upon…

In computerized adaptive testing (CAT), new or experimental items are frequently administered alongside operational tests to gather the pretest data needed to replenish and replace item pools. The two basic strategies used to combine pretest and operational items are embedding and appending. Variable-length CATs are preferred because of the…

TAILOR is a computer program that uses the implied orders concept as the basis for computerized adaptive testing. The basic characteristics of TAILOR, which does not involve pretesting, are reviewed here and two studies of it are reported. One is a Monte Carlo simulation based on the four-parameter Birnbaum model and the other uses a matrix of…

The Head Start Measures Project was a 3-year study to develop a set of measures designed specifically for Head Start children. The measures are based on a path-referenced approach to assessment, in which children's performance is described in terms of their position along paths of development. A path is defined as a sequence of skills within a…

Information provided by typical and improved conventional classroom achievement tests was compared with information provided by an adaptive test covering the same subject matter. Both tests were administered to over 700 college students in a general biology course. Using the same scoring method, adaptive testing was found to yield substantially…