Competency evaluation rating forms are widely used to assess a range of global and specific psychology practitioner competencies during and at the end of clinical placements. Surprisingly, there is little research examining the dimensional structure or the hierarchical clustering of items on these ratings. The current, multisite study examined supervisor ratings of clinical psychology trainees (N = 204) on the Clinical Psychology Practicum Competencies Rating Scale (CΨPRS). Based on the proximity criterion chosen, hierarchical clustering yielded either nine clusters or four super clusters: Good Practitioner Attributes and Conduct, Scientist Practitioner and Professional Management, Assessment and Intervention, and Psychological Testing. The study also tracked the developmental trajectory of competency attainment. CΨPRS ratings differentiated groups between early but not between later stages of training. Measurement issues and implications for training and practice are discussed.