For trinary partial credit items, the shape of the item information and item discrimination functions is examined in relation to the item parameters. Conditions under which these functions are unimodal and bimodal are discussed, and the locations and values of maxima are derived. Practical relevance of the results is discussed. (SLD)

This book is a compendium of recent item response theory (IRT) research that reviews 27 IRT models. The book contains a historical overview of IRT followed by six sections that deal with the application of a particular IRT model or set of models. (SLD)

A formal framework is presented for determining which of the distractors of multiple-choice test items has a small probability of being chosen by a typical examinee. The framework is based on a procedure similar to an indifference zone formulation of a ranking and election problem. (Author/BW)

This discussion of new methods for calibrating item response theory (IRT) models looks into new optimization procedures, such as the Genetic Algorithm (GA) to improve on the use of the Newton-Raphson procedure. The advantages of using a global optimization procedure like GA is that this kind of procedure is not easily affected by local optima and…

This paper describes and evaluates the use of decision theory as a tool for classifying examinees based on their item response patterns. Decision theory, developed by A. Wald (1947) and now widely used in engineering, agriculture, and computing, provides a simple model for the analysis of categorical data. Measurement decision theory requires only…

A test theory model based on the Thurstone judgmental model is described. By restricting various parameters of the model, 3 Rasch models, 2 pseudo-Rasch models, 3 two-parameter models, and a Weber's Law model are derived. (Author/CTM)

Generating a test from an item bank using a criterion based on classical test theory parameters poses considerable problems. A mathematical model is formulated that maximizes the reliability coefficient alpha, subject to logical constraints on the choice of items. Theorems ensuring appropriate application of the Lagragian relation techniques are…

A new method of measuring item bias based on the latent class model proposed by the author is suggested. A test for item bias is also suggested that is based on standard asymptotic results. (Author/DWH)

Two-group classification is discussed when a unidimensional latent trait "theta" is appropriate for explaining data. If data have a monotone likelihood ratio, then optimal allocation rules can be based on its magnitude when allocation must be made to one of the two groups related to the unidimensional latent trait. (SLD)

An item response theory model based on the Rasch model is proposed for composite tasks, those decomposed into subtasks of different kinds. The model, which is illustrated with an application to spelling tasks, constrains the difficulties of the composite tasks to be linear combinations of the difficulties of the subtask items. (SLD)

Test data generated according to two different multidimensional item response theory (IRT) models were compared at both the item response level and the test score level to determine whether measurable differences between the models could be detected when the data sets were constrained to be equivalent in terms of item "p"-values. The…

Following a brief discussion of test construction by linear programing, the results of a study by F. B. Baker and others (1988) with respect to a uniform target is replicated. It is demonstrated that the result depends on characteristics of the item pool. (SLD)

How item bias indexes based on item response theory (IRT) identify bias that results from multidimensionality is demonstrated. Simulation results suggest that IRT-based bias indexes detect multidimensional items with bias but do not detect multidimensional items without bias. They also do not confound between-group differences on the primary test.…

A procedure for obtaining Rasch model estimates of item difficulty and of ability is detailed. The procedure approximates the optimal but difficult to obtain "unconditional" estimates. (JKS)

The purpose of the present paper is to derive linear equating methods for the common item nonequivalent populations design from explicitly stated congeneric type test score models. The equating methods developed are compared with previously developed methods and applied to five professionally constructed examinations administered to approximately…