In September 2022, New York City Public Schools (NYCPS) announced a major expansion of work-based learning programs for high school students. The initiative, which provides 3,000 students with apprenticeships in technology, business, education, and healthcare, is one part of a larger vision for career-connected learning for all students throughout the system (NYCPS, 2022). While the scope of this apprenticeship program and the broader Student Pathways initiative is new, the effort to link students to work has been underway for decades. ExpandED STEM Options (ES Options)--part of the broader Options initiative led by ExpandED Schools--is one example. Prior research suggests initiatives like ES Options are difficult to sustain and scale. Apprenticeships are time-consuming. Participants (on both the school and industry sides) typically have conflicting responsibilities and resource constraints. In this study, the Research Alliance focused on learning why more interested students were not completing the program. Based on an analysis of students' progression through the program, as well as interviews with staff, observations of ES Options programming in action, and student surveys, it was found that four key factors affected student participation in the apprenticeships and internships: school support, financial incentives, length of time between application and enrollment, and competing demands. The authors believe that these factors may serve as leverage points to increase participation in ES Options and other similar programs.