Provides a conceptual basis for understanding factor analysis as an analytical technique. Illustrates the basic concepts of factor analysis through Edward L. Rainbow's data from a study of variables influencing students' musical aptitude. Suggests that this technique is most appropriate in music applications where the interrelationships between…

The overidentification of structural equation models with latent variables is discussed. The use of two- and three-indicator models is not recommended since such models do not allow a testing of the crucial assumption of unidimensionality among indicators in most cases. Models with four or more indicators may be more sensitive to departures from…

This paper provides an up-to-date review of the relationship between item response theory (IRT) and (nonlinear) common factor theory and draws out of this relationship some implications for current and future research in IRT. Nonlinear common factor analysis yields a natural embodiment of the weak principle of local independence in appropriate…

This paper responds to a 1992 study in which it was argued that the structure of intelligence in adults with severe mental retardation deviates from Greenspan's model, in which social and practical intelligence form separate factors. Application of confirmatory factor analysis to the original correlation matrix found the Greenspan model to be…

This paper discusses inconsistencies in Greenspan and McGrew's argument that confirmatory, rather than exploratory, factor analysis should be utilized in testing Greenspan's model of adaptive intelligence in adults with severe mental retardation. It is argued that problems with the data set should be addressed through further research rather than…

The general goal of this paper is to help researchers conduct appropriately designed goodness of fit studies for item response model applications. The specific purposes are to describe: (1) an up-to-date set of promising and useful methods for addressing a variety of goodness of fit questions; and (2) current research studies to advance this set…

This paper discusses the theoretical scope and practical applicability of generalizability (G) theory through the principle of symmetry. Major ideas are summarized and factors hindering applications of G theory in research conducted in French-speaking Europe are presented. The principle of symmetry affirms that any factor of a design can be…

Provides an exercise for introducing research methods to undergraduates. The students view a graph revealing that left-handed people are underrepresented in older age groups. Small group discussions attempt to explain this phenomenon. A follow-up class discussion focuses on the different approaches and methods available for interpreting the data.…

Approaches to studying the relationships between stress and school organizational sources of stress were examined. Rather than sampling a number of schools and school average data indicating school health and stress levels in these schools, simple teacher samples and teacher-level analyses were used. For a sample of 1300 high school teachers in…