“It Should Be a Priority”: Lessons Learned by Head Start Leaders, Staff, and Parent Facilitators Delivering a Multi-Site Parent-Centered Child Obesity Prevention Intervention

<b>Background</b>: Head Start, a federally funded preschool for low-income families, offers a unique space for interventionists to equitably reach parents and children, and promote healthful behavior for chronic disease prevention. However, determinants of implementation in this context remain understudied, hindering opportunities for improvement. We aim to identify organization-level factors affecting implementation of an obesity prevention program, as relayed by implementation partners at Head Start. <b>Methods</b>: Communities for Healthy Living (CHL), designed and implemented with Greater Boston Head Start (<i>n</i> = 16 programs across <i>n</i> = 2 agencies), is a cluster-randomized obesity prevention trial offering enhanced nutrition support, media campaign, and a parenting program. The current study draws on two years (2017-19) of data collected from Head Start implementation partners. Pre-implementation, staff completed anonymous surveys: implementation readiness (<i>n</i> = 119), staff training evaluation (<i>n</i> = 166), and facilitator training evaluation (<i>n</i> = 22); response frequencies were tabulated. Mid-implementation, staff and leadership participated in focus groups (<i>n</i> = 3 groups with <i>n</i> = 16 participants) and interviews (<i>n</i> = 9); transcripts were analyzed using a deductive-inductive hybrid approach, grounded in the Consolidated Framework for Implementation Research. <b>Results</b>: Most staff strongly agreed or agreed they understood their role (98.8%), planned on recruiting parents (98.2%), and reported commitment to implementation (92.5%); however, fewer identified CHL as a priority (69.7%) and were confident in their ability to coordinate efforts (84.9%), handle challenges (77.3%), and receive support (83.2%). Thematic analysis yielded implementation facilitators, including mission alignment, partner engagement in design, allocation of intervention-specific resources, and expressed leadership support. Barriers included strains imposed on staff workflow, a lack of shared responsibility, and challenges in coordinating CHL activities amidst competing Head Start programs. <b>Conclusions</b>: Responsive efforts to address deliverer-identified barriers to implementation may include reducing intervention impact on preexisting workflow, as well as clearly distinguishing intervention activities from preexisting Head Start programs.