Three-dimensional response surface plots are presented for several hierarchical clustering methods and simulated core group data structures. Influence patterns explain some results from previous validation research on clustering methods and have significant implications for the choice of clustering methods in empirical research. (SLD)

In Varimax rotation, permutations and reflections can give rise to the phenomenon that certain pairs of columns are consistently skipped in the iterative process, causing Varimax to terminate at a nonstationary point. This skipping phenomenon is demonstrated, and how to prevent it is described. (SLD)

Fundamental concepts of Gaussian Recognition Theory are reviewed, and one of the major theorems used to test for perceptual independence among stimulus dimensions is disputed through a relatively simple counterexample. An amended version of the theorem, Theorem 4, is offered, and a simulation demonstrates its utility. (SLD)

Business simulation can give everyone a fresh overview of the business. Well-designed games and simulations can help players understand why change is necessary and can create within the learner a demand for know-how that no lecture can match. (JOW)

A theoretical four-mass model of the larynx was developed to simulate laryngeal biomechanical behavior and used to evaluate states of asymmetric laryngeal vibration. Simulations of laryngeal paralyses were compared with data on glottal vibration in observed laryngeal function. (Author/JDD)

Results from a simulation study confirm that under reasonably representative conditions the replication demonstrated by clustering mean profiles from several preliminary cluster analyses of independent subsets of multivariate profiles is an adequate criterion for inferring the correct number of underlying populations when they are reasonably well…

Explores the concept of validity in relation to games and simulations, including four aspects of validity that apply to simulations and games (psychological reality, structural validity, process validity, and predictive validity). Factors that may threaten validity during game design are discussed, and suggestions are made to avert these threats.…

The use of ex post (historical) simulation statistics as means of evaluating latent growth models is considered, and a variety of simulation quality statistics are applied to such models. Results illustrate the importance of using these measures as adjuncts to more traditional forms of model evaluation. (SLD)

Proposes a method for post hoc contrasts based on subsets of treatment groups, and simulates critical values from the appropriate multivariable F-distribution to be used in place of those associated with Scheffe's test (H. Scheffe, 1953). The proposed method and its critical values provide a uniformly more-powerful post hoc procedure. (SLD)

Demonstrates the advantages of Rao's Distance (C. Rao, 1949) over the root mean residual square for model comparisons using an analysis of a sample of multitrait-multimethod data. A simulation study shows that the true orderings of intermodel proximities are received with a fair degree of accuracy. (Author/SLD)

Presents a simple method for generating simulated plasmodes and artificial test clusters with user-defined shape, size, and orientation. For "J" clusters, indicator validity is defined as the squared correlation ratio between the cluster indicator and J-1 dummy variables. Illustrates the method through simulation. (SLD)

Describes how Random Boolean Networks can be used to simulate simple lexicons, and shows how some puzzling properties of real lexicons seem to emerge spontaneously in these models. Describes simple simulations of bilingual aphasia, and shows that a range of recovery patterns can be observed in these simulations. (Author/VWL)

Proposes generalized least squares methods in structural equation models to estimate potential mean structure parameters and to evaluate whether the given model can be augmented successfully with a mean structure. A simulation shows that a method that takes variability due to the estimate of covariance structure parameters into account performs…

Tested whether an elaborated version of the perceptual loop theory (W. Levelt, 1983) and the main interruption rule was consistent with existing time course data (E. Blackmer and E. Mitton, 1991; C. Oomen and A. Postma, in press). The study suggests that including an inner loop through the speech comprehension system generates predictions that fit…

Developed a sample-based nonanalytical degrees-of-freedom correction factor for situations sampling both subjects and conditions with measurement data departing from essentially parallel form. Assessed the application of this correction factor through a simulation study involving data sets with a range of design characteristics and manifesting…