The problem of correlating variables from different scale types is discussed. A general correlation coefficient, based on symmetrization theory, is derived. The coefficient is invariant over permitted transformations of the variables for their respective (possibly nonequivalent) scale types. (Author/JKS)

H. F. Kaiser, S. Hunka, and J. Bianchini have presented a method (1971) to compare two matrices of factor loadings based on the same variables, but different groups of individuals. The optimal rotation involved is examined from a mathematical point of view, and the method is shown to be invalid. (SLD)

Monte Carlo validation studies of clustering algorithms, including Ward's minimum variance hierarchical method, are reviewed. Caution concerning the uncritical selection of Ward's method for recovering cluster structure is advised. Alternative explanations for differential recovery performance are explored and recommendations are made for future…

The fundamental problems that ipsative measures impose for factor analysis are shown analytically. Normative and ipsative correlation matrices are used to show that the factor pattern induced by ipsativity will overwhelm any factor structure seen with normative factor analysis, making factor analysis not interpretable. (SLD)

Limitations of dummy coding and nonsense coding as methods of coding categorical variables for use as predictors in multiple regression analysis are discussed. The combination of these approaches often yields estimates and tests of significance that are not intended by researchers for inclusion in their models. (SLD)

Conceptual rationales from five research contexts are presented, which all posit unmeasured variables that interact with observed independent variables to produce a complete model of the dependent variable. Strategies for overcoming related difficulties are outlined, including increased longitudinal assessment, oversampling of levels of…

Classical methods for detecting outliers deal with continuous variables. These methods are not readily applicable to categorical data, such as incorrect/correct scores (0/1) and ordered rating scale scores (e.g., 0,..., 4) typical of multi-item tests and questionnaires. This study proposes two definitions of outlier scores suited for categorical…

First- and second-round commentaries on an article by L. Guttman are presented. The following authors responded, with two articles each: (1) E. E. Roskam and J. Ellis; (2) P. H. Schonemann; (3) A. R. Jensen; (4) J. C. Loehlin; and (5) J.-E. Gustafsson. (SLD)

While the author and Raymond Cattell approach personality study differently, their similar conclusions reveal their constructs and theories as complimentary, not contradictory. They agree on major issues: the existence of general personality traits with consistent associated behaviors, the relevance of multivariate studies, and the importance of…

Results of a reanalysis of previously published data (B. M. Byrne, 1989) support the correlated uniqueness model, diagnostic tests of the validity of confirmatory factor analysis (CFA), multitrait multimethod (MTMM) solutions, inclusion of external validity in MTMM design, and application of factorial invariance to test stability of CFA-MTMM…

Argues that Jensen's article contains an inaccurate and misleading account of Spearman's work and distorts the basic concepts of factor analysis. The target article has failed in all its main objectives; its major failing is a result of the irrelevance of factor analysis to the study of group differences. (SLD)

Raymond Cattell's efforts to sort out the relationships of genetic or environmental patterns to personality factors have contributed to behavior genetics. Early writings on the projected decline of intelligence in Britain, studies using Multivariate Abstract Variance Analysis, and other miscellaneous studies on personality factors and mental…

In this overview of his research in personality theory, Cattell describes the play of people, situations, and, ideas enacted over 30 years in his University of Illinois laboratory. Establishing meaningful empirical measurement methods was the foundation for further research into many aspects of personality development. (BS)