Poor participant engagement threatens the potential impact and cost-effectiveness of public health programmes preventing meaningful evaluation and wider application. Although barriers and levers to engagement with public health programmes are well documented, there is a lack of proven strategies in the literature addressing these. This paper details the development of a participant engagement intervention aimed at promoting enrolment and attendance to a community-based pre-school obesity prevention programme delivered in UK children's centres; HENRY (Health, Exercise, Nutrition for the Really Young). The Behaviour Change Wheel framework was used to guide the development of the intervention. The findings of a coinciding focused ethnography study identified barriers and levers to engagement with HENRY that informed which behaviours should be targeted within the intervention to promote engagement. A COM-B behavioural analysis was undertaken to identify whether capability, opportunity or motivation would need to be influenced for the target behaviours to occur. APEASE criteria were used to agree on appropriate intervention functions and behaviour change techniques. A multi-level participant engagement intervention was developed to promote adoption of target behaviours that were proposed to promote engagement with HENRY, e.g. ensuring the programme is accurately portrayed when approaching individuals to attend and providing 'taster' sessions prior to each programme. At the local authority level, the intervention aimed to increase buy-in with HENRY to increase the level of resource dedicated to engagement efforts. At the centre level, managers were encouraged to widen promotion of the programme and ensure that staff promoted the programme accurately. HENRY facilitators received training to increase engagement during sessions, and parents that had attended HENRY were encouraged to recruit their peers. This paper describes one of the first attempts to develop a theory-based multi-level participant engagement intervention specifically designed to promote recruitment and retention to a community-based obesity prevention programme. Given the challenges to implementing public health programmes with sufficient reach, the process used to develop the intervention serves as an example of how programmes that are already widely commissioned could be optimised to enable greater impact.
Keywords: Behaviour Change Wheel; Children’s centres; Intervention; Obesity prevention; Participant engagement; Public health.