Communities for Healthy Living (CHL) A Community-based Intervention to Prevent Obesity in Low-Income Preschool Children: Process Evaluation Protocol.

Background: Process evaluation can illuminate barriers and facilitators to intervention implementation as well as the drivers of intervention outcomes. However, few obesity intervention studies have documented process evaluation methods and results. Community-based participatory research (CBPR) requires that process evaluation methods be developed to (a) prioritize community members' power to adapt the program to local needs over strict adherence to intervention protocols, (b) share process evaluation data with implementers to maximize benefit to participants, and (c) ensure partner organizations are not overburdened. Co-designed with low-income parents using CBPR, Communities for Healthy Living (CHL) is a family-centered intervention implemented within Head Start to prevent childhood obesity and promote family well-being. We are currently undertaking a randomized controlled trial to test the effectiveness of CHL in 23 Head Start centers in the greater Boston area. In this protocol paper, we outline an embedded process evaluation designed to monitor intervention adherence and adaptation, support ongoing quality improvement, and examine contextual factors that may moderate intervention implementation and/or effectiveness.

Methods: This mixed methods process evaluation was developed using the Pérez et al. framework for evaluating adaptive interventions and is reported following guidelines outlined by Grant et al. Trained research assistants will conduct structured observations of intervention sessions. Intervention facilitators and recipients, along with Head Start staff, will complete surveys and semi-structured interviews. De-identified data for all eligible children and families will be extracted from Head Start administrative records. Qualitative data will be analyzed thematically. Quantitative and qualitative data will be integrated using triangulation methods to assess intervention adherence, monitor adaptations, and identify moderators of intervention implementation and effectiveness.

Discussion: A diverse set of quantitative and qualitative data sources are employed to fully characterize CHL implementation. Simultaneously, CHL's process evaluation will provide a case study on strategies to address the challenges of process evaluation for CBPR interventions. Results from this process evaluation will help to explain variation in intervention implementation and outcomes across Head Start programs, support CHL sustainability and future scale-up, and provide guidance for future complex interventions developed using CBPR.

Trial Registration: ClinicalTrials.gov, NCT03334669 . Registered on October 10, 2017.