This study examines the underlying structure of the Clinical Experience Rubric (CER), which is designed to assess preservice teachers' dispositions during the clinical experiences. Dispositions were conceptualized as being a multidimensional construct with three related factors: (a) professionalism, (b) teaching quality, and (c) relationship with others. In the study, 320 preservice teachers were rated by their cooperating teacher on the CER. A confirmatory factor analysis, based on a three-factor model, was performed through LISREL. The results suggest the three-factor model is a reasonable fit and is a significant improvement in fit over a one-factor model. (Contains 3 tables.)