Access to effective and comprehensive transition programming is pivotal to transition of youth with disabilities to work and independent living. Successful programs often blend key ingredients, including individualized educational planning, career development, work experiences in secondary school, and interagency partnerships/collaborations. Through a comparative analysis of the New York State transition program data, and the National Longitudinal Transition Study 2 (NLTS2) data, this study empirically demonstrated the simultaneous contributions of various transition program elements to student postsecondary outcomes using mediation models. In addition, the technique of using propensity score analysis for balancing the two comparison cohorts, applied in this study, contributes to the arsenal of analytical techniques for evaluating the impact of transition to adulthood programs. [This research was funded by the U.S. Department of Health and Human Services, Center for Medicare and Medicaid Services.]