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…

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…

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…

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)