This article examines Guttman's facet theory (FT) and compares it to factor analysis (FA) in the context of two research studies. FT is examined in terms of its advantages and disadvantages compared to FA for theory development and confirmation. Two studies provide insights into the utility of FT. The first describes ideal student traits as perceived by prospective teachers. Using FT and smallest space analysis (SSA) confirmed the theory by displaying the accord between the facets in the mapping sentence and the distribution of the items in a multidimensional space. The second describes teacher professionalism and teaching context as perceived by teachers who completed a version of the Talbert and McLaughlin questionnaire. FT and SSA confirmed the theory and identified the subscales and dynamic relationships between them. By using the definitional mapping sentence of FT and SSA, the multidimensional theory and structural validity of the findings in the two studies were confirmed
