This study leveraged the knowledge and experiences of youth with disabilities, their families, and transition stakeholders to model how the frequency of family engagement activities and services and employment preparation activities and services predict the frequency of youth development activities and services. This information was obtained through a secondary data source of responses to the Transition Discoveries Quality Indicator Survey, a tool designed to gather data on high-quality transition as defined by the Transition Discoveries Framework (Kester et. al., 2021). The overarching goal was to model effective transition-in-context and how factors in the implementation environment influenced the frequency of the predictors of youth development activities and services. A web of significant relationships was identified through latent modeling, logistic regression, and correlational relationships. In particular, the frequency of family engagement activities and services was found to be a significant predictor of the frequency of youth development activities and services. While significant, to a lesser extent, the frequency of employment activities and services was also a predictor of youth development. Results also showed that access staff to self-guided learning materials, access to mentorship, and the extent to which practices are adapted to meet organizational needs are all significant predictors of the frequency of family engagement and employment activities and services. Implications for research, practice, and policy are discussed, including further modeling of effective transition, developing positive implementation environments, and expanding current definitions of compliance for effective transition planning. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]