Confirming the Structure of a Ten-item Expagg Scale Using Confirmatory Factor Analysis

The short Expagg scale is a psychometric measure of social representations of expressive and instrumental aggression developed by Campbell, Muncer, McManus and Woodhouse (1999). Confirmatory factor analysis (CFA) was used to compare the 16-item and 10-item versions of the scales on their goodness of fit to a proposed two-dimensional model. On a sample of 1,000 respondents, the 5-item version showed superior fit measures and exceeded three criteria of fit adequacy (CFI = .93, GFI = .97, RMSEA =.06). We conclude that the ten-item Expagg is not only more convenient to use than the longer version but that it provides a better fit to the underlying two-dimensional conceptual structure than the longer version. Current Research in Social Psychology (Vol. 10, No. 15) (Driscoll, Campbell, & Muncer)