Managed care and the corporatization of health care in the United States present challenges to medical professionalism. The defining, promoting, and teaching of medical professionalism have therefore become major concerns for medical educators. Consequently, the need for a systematic assessment of professionalism has become apparent. In 2002, the Medical Student Performance Evaluation Committee of the Association of American Medical Colleges developed and published a Draft Professionalism Assessment Form. The Keck School of Medicine of the University of Southern California pilot tested this instrument during the fall and spring semesters of 2005-2006. The purpose of this study was to begin the process of validating this instrument by determining inter-rater reliability. Within the section titled Review of Literature, the work relates five professional development theories to currently employed methods of assessment. This innovative classification system contributes to our understanding of professional development and evaluation instruments.