Methods Factors In Multitrait-Multimethod Matrices : Multiplicative Rather Than Additive?

When traits are measured by the same method (or at the same time) the intertrait correlations are higher than when the intertrait correlation is across methods. An empirical investigation of the nature of such method factors is reported, in which the method factors seem to operate in a multiplicative rather than additive way, or in which larger method loadings are associated with larger trait loadings. An implicit-theory-of-personality explanation is offered for the case of ratings as methods. An attenuation model has more general applicability to the oases illustrated. The possibility is raised that the finding, if confirmed in other domains, demonstrates a fundamental innappropriateness of factor analysis for the componential analysis of indi6dual differences data.