Scales constructed using principal components and Rasch measurement methods are compared under conditions of unclear constructs and marginal sample sizes with three data sets of increasing complexity. Results of the two methods were identical when data were stable and the structure unidimensional. (SLD)

The underlying structure of the Depression scale of the revised Minnesota Multiphasic Personality Inventory (MMPI-2) was studied using dichotomous Rasch model and factor analysis with the normative sample of 2,600 subjects. Results reveal two distinct subscales (mental depression and physical depression) in place of a homogenous set of items. (SLD)