A convention commonly used to describe interaction effects within moderated regression frameworks was examined through logical exposition and a Monte Carlo approach to simulate various moderator conditions. Results, which indicate that the convention may lead to incorrect inferences, are discussed in terms of interpreting moderator effects. (SLD)

Virtual Reality (VR) is a computer-created sensory experience that so completely immerses participants that they barely can distinguish this "virtual" experience from a real one. VR promises trainers the ultimate method of simulation. (Author)

Responses to a 50-item, 4-choice test were simulated for 1,000 examinees under conventional formula-scoring instructions. Based on 192 simulation runs, formula scores and expected formula scores were determined for each examinee allowing and not allowing for inappropriate omissions. (TJH)

Exact testing was evaluated as a method for conducting Mantel-Haenszel differential item functioning (DIF) analyses with relatively small samples. A series of computer simulations found that the asymptotic Mantel-Haenszel and the exact method yielded very similar results across sample size, levels of DIF, and data sets. (SLD)

Presents a connectionist approach to modeling that relies on neural networks to control conventional simulations of multimedia clinical patient simulations. These neural networks simplify the medical expert's task of validating and maintaining patient simulations with diagnostic capabilities and serves as the basis of clinical decision support…

A simulation study compares nonhierarchical clustering capabilities of a class of neural networks using Kohonen learning with a K-means clustering procedure. The focus is on the ability of the procedures to recover correctly the known cluster structure in the data. Advantages and disadvantages of the procedures are reviewed. (SLD)

Reviews the literature concerning practical computer-based simulation systems for the management of construction projects and/or firms and describes a conceptual model of a prototype system that simulates the decision making of construction site management. Research and development required to produce the system for use in industry is discussed.…

Virtual reality, a three-dimensional simulation technology, may best be used (1) when training mistakes would be costly; (2) when the environment cannot be experienced in the real world; (3) to improve human-machine interfaces; (4) to make training situations real; and (5) to make the perceptible imperceptible. (SK)

Effectiveness of jackknife methods in reducing bias in estimation of the log-1 autocorrelation parameter p1 was evaluated through a Monte Carlo study using sample sizes ranging from 6 to 500. These estimates appear less biased in the small sample case than many that have been investigated recently. (SLD)

The nonparametric Mokken model of test data was compared with parametric models using simulated data through latent class analysis. It is demonstrated that latent class analysis provides a consistent comparison of item response models. (SLD)

The first of two articles discusses virtual reality (VR) and online databases; the second one reports on an interview with Thomas A. Furness III, who defines VR and explains work at the Human Interface Technology Laboratory (HIT). Sidebars contain a glossary of VR terms and a conversation with Toni Emerson, the HIT lab's librarian. (LRW)

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.…

Simulations show effects of variability on the maximum contingency that can be displayed by an average 2 X 2 table. Results help explain the regularity known as the Tulving-Wiseman law, as well as conditions under which exceptions are found. Dangers posed by variability and Simpson's paradox are discussed. (SLD)

Considers the role of the simulation designer in the development of business enterprise simulations used in collegiate business education. Topics include the designer's knowledge domain; conflicting business administration theories in accounting, finance, economics, marketing, production, and income tax; and other designer issues. (LRW)

Some uniqueness properties are presented for the PARAFAC2 model for covariance matrices, focusing on uniqueness in the rank two case of PARAFAC2. PARAFAC2 is shown to be usually unique with four matrices, but not unique with three unless a certain additional assumption is introduced. (SLD)