Issue 1
Vol. 44
2002

Factor analysis in personality research:
Some artefacts and their consequences for psychological assessment

Helfried Moosbrugger & Johannes Hartig

Summary
Exploratory factor analysis (EFA) is one of the most frequently applied statistical methods in personality research; many trait theories are mainly based on EFA results. Given the widespread use and the strong influence of EFA techniques, it is advisable to critically inspect the ideas underlying these methods and to consider in which way their application may lead to artefacts in personality research. In this paper the basic ideas of exploratory factor analysis are outlined and the major steps in factor analytic research are described: the selection of relevant variables, the choice of a measure of association between these variables, the sampling procedure, the extraction of the initial factors, the identification of non-trivial factors, factor rotation and interpretation of the final loading pattern. Subsequently, some consequences and artefacts related to the decisions that have to be made at each of these steps are considered. Among other points the risks of over- or underestimating the number of non-trivial factors, difficulty factors resulting in the analysis of binary variables and problems related to the interpretation of orthogonal and oblique factor solutions are discussed.

Key words: exploratory factor analysis, binary variables, oblique factor solution, personality questionnaire

Univ. Prof. Dr. Helfried Moosbrugger
Dipl.-Psych. Johannes Hartig
Department of Psychology
Johann Wolfgang Goethe-University of Frankfurt
Mertonstraße 17
D-60054 Frankfurt am Main/Germany