Designing a context-specific intervention in practice: learning from a school-based physical activity intervention

Background
Public health interventions need to be designed for the intervention setting. Traditionally, to maximise internal validity, school-based pupil physical activity interventions deliver an identical programme across all settings. However, an interventions’ success will depend on the context in which it is implemented, i.e. a schools’ social, cultural, economic, environmental and other characteristics. In this paper we use the PASSPORT (Physical Activity via a School-Specific PORTfolio) study as a case study for designing a context-specific public health intervention. We used a portfolio approach that allows schools to select and deliver tailored intervention content that is most suitable to their setting. We outline how we developed the intervention and draw out key learning from this for public health interventions generally.

Methods
The PASSPORT intervention was developed across multiple research steps that were designed to progressively build key knowledge. Formative studies included: a scoping review of intervention components; school staff interviews; a rapid ethnography in three primary schools; and a school survey. These then informed the intervention design and content, which were developed via two mechanisms: the co-design of the intervention tool with primary school staff and by centring school expertise and experience in intervention design and content. Finally, we conducted a pilot study to learn from both the delivery of the intervention and associated evaluation data collection.

Key learning
Key learning from the intervention design and development has been gathered around four areas: Ground intervention design in a range of data and insight, centre user experience, design for intervention flexibility and user autonomy, and, build in processes to test and iterate.

Conclusions
Each of the formative studies and the intervention design steps provided parts of the complex picture of intervention context and design needs. Combined, the results of the studies supported the development of a context-specific intervention.