BACKGROUND: Whole system approaches (WSAs) are increasingly adopted to improve public health practice and outcomes. This paper reports on the evaluation of the Children and Families Pilot (referred to throughout as PIPYN), which is a combined WSA and nested family-based intervention (FBI) that aims to reduce levels of childhood obesity (age 3-7). Piloted between 2021 and 2025 in three local communities in Wales, United Kingdom (UK), this evaluation aimed to examine implementation of the WSA and FBI, and understand perceived impacts of both components, including system change across pilot areas, in relation to childhood overweight and obesity. METHODS: Using a qualitative study design, 19 semi-structured interviews were held with PIPYN programme development stakeholders at the national level and local stakeholders involved in implementation. A documentary analysis was used to summarise pilot development and to contextualise interview findings. Thematic analysis was used to identify key themes and explore perceived impacts of the pilot. RESULTS: Four thematic areas are presented to summarise programme viewpoints relating to: 1) effective systems working for childhood overweight and obesity; 2) collaborative communities; 3) Family-Based Intervention (FBI) implementation and uptake; and 4) barriers and facilitators to programme delivery. Across themes, stakeholders perceived the WSA as an effective method to support a systemic shift across agencies to prevent childhood overweight and obesity. Key steps involved strengthening stakeholder partnerships, adapting approaches to support local systems, and addressing gaps in weight management services through the FBI. Stakeholders identified substantial challenges in monitoring and evaluation, with data incompleteness for the FBI (particularly for anthropometric data) and limited capability to assess systems-level impacts, imposing constraints on evaluation of programme implementation and effectiveness. CONCLUSIONS: There is a need for well-defined intervention and system boundaries to guide set-up and implementation of WSAs. Related to this, future efforts require a focus on the development and promotion of applied, practice-oriented guidance for implementing WSAs. Clear monitoring and evaluation metrics are needed that are practice-friendly and integrated from the outset of programme delivery.
Kolosowska et al. (Mon,) studied this question.