About 45 R packages to analyze data using item response theory (IRT) have been developed over the last decade. This article introduces these 45 R packages with their descriptions and features. It also describes possible advanced IRT models using R packages, as well as dichotomous and polytomous IRT models, and R packages that contain applications…

Hierarchical classes models are models for "N"-way "N"-mode data that represent the association among the "N" modes and simultaneously yield, for each mode, a hierarchical classification of its elements. In this paper we present a stochastic extension of the hierarchical classes model for two-way two-mode binary data. In line with the original…

In psychological research, one often aims at explaining individual differences in S-R profiles, that is, individual differences in the responses (R) with which people react to specific stimuli (S). To this end, researchers often postulate an underlying sequential process, which boils down to the specification of a set of mediating variables (M)…

Federal standards established in 1997 allow respondents to select multiple-race categories. These new standards changed the single-race subgroup definitions that the government has required since 1977. Meta-analysis, research on long-term assessment trends, and other research involving historical comparisons must account for the definitional…

Reviews the problems of classifying gaming techniques and suggests a heuristic approach as one solution. Definitions of simulation, models, role, and game and play are discussed to help develop a classification based on a technique called gaming simulation. (Author/LRW)

This paper reviews work on the representation of knowledge from within psychology and artificial intelligence. The work covers the nature of representation, the distinction between the represented world and the representing world, and significant issues concerned with propositional, analogical, and superpositional representations. Specific topics…

Suggests new method of external distribution called tree partitioning that involves use of binary tree to split incoming file into successively smaller partitions for internal sorting. Number of disc accesses during a tree-partitioning sort were calculated in simulation using files extracted from British National Bibliography catalog files. (19…

This paper discusses the principles underlying discriminant analysis and constructs a simulated data set to illustrate its methods. Discriminant analysis is a multivariate technique for identifying the best combination of variables to maximally discriminate between groups. Discriminant functions are established on existing groups and used to…

Clarifies appropriateness of certain simulation approaches by distinguishing between different types of simulations--experimental, predictive, evaluative, and educational--on the basis of purpose, assumptions, procedures, and criteria for evaluating. The kinds of questions each type best responds to are discussed. (65 references) (MBR)