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

1. Introduction

Public health interventions should be designed for their setting, addressing the needs of the people they are impacting and the systems they work within.^1,2 It is increasingly recognised that this means intervention settings should be viewed as complex adaptive systems, and that interventions in turn must adapt to that complexity to be successful.³ In children’s physical activity research, school-based interventions have great potential to support large numbers of children to be active.^4–6 However, despite a small number of exceptions, research has shown, in general, that these interventions have not increased children’s moderate-to-vigorous intensity physical activity (MVPA).^7–13 This is a critical issue, as physical activity is essential to children’s physical and mental health and wellbeing.^14–16 However, the majority of children are not meeting the recommended minimum levels of physical activity^17,18 in the UK or globally.^19–22 Evidence shows that physical activity levels decline across childhood and adolescence,^23–25 and the transition from primary to secondary appears to be a key moment in this decline.²⁶ Thus, primary school is an important setting for interventions to slow or reverse this decline.²⁵ Traditionally, school-based pupil physical activity interventions (as with many public health interventions) take a ‘one-size-fits-all’ approach, designed to deliver an identical programme across all schools or settings with a focus on internal validity. A key aspect that is assumed independent from the active component of an intervention in this approach is the context in which it is implemented, i.e., a schools’ social, cultural, economic, environmental and other characteristics.²⁷ We have suggested that this could be a key factor in the limited success of school-based physical activity interventions,²⁷ and can contribute to low external validity and a lack of intervention sustainability and success when scaled up.²⁸ Contextual variation in school-based interventions should be no different from real-world interventions implemented in other environments. Therefore, this is potentially an issue for all public health interventions generally.

PASSPORT (Physical Activity via a School-Specific PORTfolio) is a five-year project at the University of Bristol that aims to develop and evaluate a context-specific school-based physical activity intervention that attempts to address the problem outlined above. Therefore all formative studies, development work, pilot, and trial and evaluation were funded and delivered in this period. The intervention is being evaluated with a stepped-wedge randomised controlled trial²⁹ and is focused on Year 5 (aged 9-10) due to the potential of improving physical activity participation in this age group before the transition to secondary school and to establish lifelong habits. The central question at the outset of this study was to explore and establish what was meant by ‘context’ in relation to primary school pupil physical activity, and what a ‘context-specific’ intervention design could look like.²⁷ We hypothesised that an intervention where content is optimised to its local context would maximise impact on pupil physical activity outcomes and could have population level impact. One way we could design a context-specific intervention is with a portfolio approach that allowed schools to select and deliver tailored intervention content that would be most suitable to their setting.

In this paper we use the development of the PASSPORT intervention as a case study for designing context-specific interventions. To achieve this aim, this paper has four elements:

Ethical approval

All studies with participants outlined in this paper received ethical approval from the University of Bristol Research Ethics Committee. Their individual references are: school staff interviews (Ref: 15866 19/10/2023), rapid ethnography (Ref: 16095 18/01/2024), school survey (Ref: 20041 06/08/2024), co-design workshops (Ref: 20957 23/08/2024), and pilot study (Ref: 23839 11/03/2025).

Consent

Across all studies informed consent or assent was obtained from all participants.³⁰ All participating schools signed school study agreements. All school staff and wider school community members provided written consent to participate as an individual in a research activity, with the exception of observational data collected in the rapid ethnography, where lead staff members provided verbal consent. This was deemed most feasible in consultation with schools, where observation of lessons is a day-to-day practice. All school staff were provided with study information sheets, consented to arrange an observation, and consented again for the observation to go ahead. In our studies that involved minors, parents provided written consent and pupils written assent. Pupil participants in the creative research activities, part of the rapid ethnography, provided written assent on paper at the start of the activity. Pupil participants in the pilot study provided written assent via the family consent form, through which parents and children consented to participate in the study.

Patient and public involvement

School staff, parents, and pupils have informed each formative study described in this paper from the design stage, commenting on and shaping data collection plans, information sheets, topic guides and other communication and recruitment processes and materials. Details of this public involvement and engagement is described in individual study papers. As part of the context-specific approach we have taken to intervention design, school staff experience was brought into the research team to lead this work. The intervention was primarily developed through co-design workshops with school staff in a range of positions and from schools with a broad range of socio-demographic and geographical contexts. Intervention content was reviewed by primary school PE expertise. Extensive engagement with staff, parents, and pupils was undertaken with the schools in the pilot study, both of which have high deprivation indicators, to develop the best approaches for inclusive and accessible participation, namely in communication and consent processes. We have established a School Advisory Group of teachers, head teachers, and PE leads to support ongoing intervention development by advising on our research planning and design, provide comment on study documents, and assist with queries or contextualising that relates to school. Members of this group represent a range of primary schools within the wider Bristol area.

2. The PASSPORT intervention

The PASSPORT intervention is a flexible, context-specific portfolio. The intervention supports primary schools to select a bespoke physical activity programme that builds on their current strengths, acknowledges limitations of the school setting, and identifies opportunities to introduce physical activity across the school day. A digital PASSPORT ‘tool’ supports staff to select their bespoke programme and support their delivery of it. The intervention takes a whole-of-school approach to physical activity³¹ and the intervention and implementation support strategies are aligned to the Consolidated Framework for Implementation Research (CFIR),^32,33 to ensure it addresses key determinants of implementation in primary school settings.

The PASSPORT intervention (outlined in Figure 1) has three main steps: 1) schools complete a baseline context assessment to provide information on their physical activity environment and practices. The context assessment captures the current provision across the school day, as well as their facilities, policies, organisational structure, and physical activity culture. 2) This information is used by the research team to recommend activity options from the portfolio that work for that school, via the tool. 3) Schools use the tool to select and deliver their bespoke programme from the recommended activities.

Figure 1. Flow of the PASSPORT portfolio intervention.

The content for the portfolio (i.e. the possible activities schools are recommended and build their bespoke programmes from) is designed along six pathways that cover physical activity opportunities across the school day and whole school community ( Figure 2). These pathways are: Physically Active and Outdoor Learning; Active Breaks; Breaktime and Lunchtime; Active Travel; Before and After School Activities; and School and the Wider Community. Schools are recommended activities from priority pathways identified through their context assessment. There is no fixed number of pathways that must be identified, and instead this is derived from a schools’ context assessment. However, we are seeking to identify the greatest potential for growth and for the programme to be focused. Again, the number of activities a school is recommended on each pathway not fixed and is derived from the context assessment, but we are balancing providing sufficient choice for a school without an overwhelming quantity. The portfolio currently has over 40 activities across the six pathways, but this can expand if additional activities are identified and is part of the interventions’ flexible design. Activities on each pathway are designed to build, establishing foundational steps that can be deepened. For example, a completed school context assessment could identify supportive senior leadership and established partnerships with local organisations as strengths, alongside limited awareness of active travel initiatives and deteriorating playground markings as areas requiring further development. It may also identify opportunities to build on, for example, by developing physically active and outdoor learning approaches in the school’s extensive outdoor spaces. Based on these findings, the school would then be recommended around 20 tailored activities across the Physically Active and Outdoor Learning, Active Travel and Breaktime and Lunchtime pathways. The school would then select approximately 5-15 of these recommended activities to create their bespoke programme.

Figure 2. The PASSPORT physical activity pathways (portfolio content).

To support the success of the bespoke programmes, all schools access a core package of resources to guide the development of school physical activity culture, staff pedagogy and skills, and alignment to school systems and priorities. Examples of these resources include guides to embedding physical activity in a school development plan or developing whole-school physical literacy. The core package resources are identical in all schools, and are incorporated into the PASSPORT tool.

Schools deliver their programmes with the support of PASSPORT staff and the ongoing use of the PASSPORT tool, which has budget, action plan, and milestone tracker functions.

3. Developing the PASSPORT intervention

The PASSPORT intervention was developed and iterated across multiple work packages, each designed to establish necessary knowledge that progressively built.

This section summarises each of these studies and work packages and describes key findings that contributed to the development of the context-specific intervention. Section 3.1) Formative work describes: a scoping review of intervention components; school staff interviews; a rapid ethnography in three primary schools; and a school survey. Section 3.2) Intervention design and content development describes how we synthesised these findings for: the co-design of the intervention tool with primary school staff, and; the portfolio content development. Figure 3 provides an overview of the development of the PASSPORT intervention, highlighting which studies provided which key insight.

Figure 3. Development of the PASSPORT intervention.

3.2. Intervention design and content development

The next step was to use data and insight from the formative work to undertake a structured approach to design a context-specific portfolio intervention and develop the portfolio content. Key to this was centring school experience in these processes to best support the development of an intervention that understood and was designed for primary school context.

Co-design of the PASSPORT tool

The PASSPORT tool that schools use to assess their context, select a bespoke programme, and support programme delivery, was developed through a co-design process with primary school staff,⁵⁰ to ensure that it was shaped by the experience and insight of the potential users. We held three ideation workshops⁵¹ between November 2024 and May 2025. Workshop 1 had 10 attendees, Workshop 2 had 10, and Workshop 3 had 6. This was a total of 11 staff from 11 local primary schools with a range of contexts (i.e. size, location, socio-economic indicators), including head teachers (n = 2), dedicated PE teachers (n = 3), class teachers with a PE lead role (n = 5), and class teachers (n = 1). Data was collected from these workshops as researcher notes, audio recordings (where functional), and through the visual materials produced. Audio recordings were transcribed and all data coded and analysed after each workshop to support the iteration of the tool design.

We used design principles to structure and plan these workshops,^52,53 following the double diamond design process⁵⁴ and applying user-centred design methods described below. The insight from the formative studies was synthesised for the workshops, by taking the findings from analyses that had been completed and by returning to original transcripts and data and coding these for tool design information. This data was revised by the team to identify and draw out constraints, opportunities, and solutions for physical activity in school and the tool, and developed into workshop activities that are described below. Through these activities the findings from formative studies were explored and validated by participants, and across the workshops we tested and refined the context assessment and iterated prototypes of the tool. Figure 4 outlines this design process, and each workshop is described below.

Figure 4. Overview of the co-design process.

In Workshop 1 (in-person), group members validated and scrutinised our understanding of the school system, different staff priorities, and the general role and landscape of physical activity in primary schools, through several activities. We used insight from the formative work to develop user personas for key school staff and pupils, which workshop members read, annotated, challenged, and validated ( Figure 5), ensuring we understood the position and priorities of each user group. We also used the formative work to create opportunity statements that highlighted key opportunities for supporting pupil physical activity in school which workshop members were asked to prioritise by most important. Improving participation of all pupils and embedding a physical activity culture were identified as areas of highest priority. Members then developed initial design ideas and features for the tool via paper prototyping activities, exploring how information could be organised and the level of detail necessary for decision-making when selecting activities, such as cost, time resource, and target audience ( Figure 6). Following Workshop 1 we developed prototypes of each part of the tool, and the idea of the core package of resources to build physical activity culture and staff also emerged at this stage.

Figure 5. Workshop 1 persona group work.

Figure 6. Workshop 1 initial ideas for the tool.

Workshop 2 (in-person) further explored issues and ideas that were identified in Workshop 1 and the core package was introduced, as well as logic models for using the tool. School physical activity culture was explored through a prioritisation activity, and members engaged with several general questions about intervention design and content that had arisen between the two workshops. Members then completed and refined a draft context assessment on paper, advising on what needed to be kept, removed, and expanded on in order to maximise the usefulness for the tool and for schools broadly. Finally, the group explored the updated paper prototypes which they iterated and refined ( Figure 7). The importance of aligning the tool and content to key policy frameworks was communicated by workshop members, namely the Ofsted inspection framework, the national curriculum for PE, and the PE and School Sport Premium, and that this would support schools in a practical and meaningful way to meet their existing demands and reporting requirements. Design features, such as how and where to best include different staff in using the tool, and the inclusion of an action plan, also arose from this workshop. Following Workshop 2 we refined the paper prototypes of the tool and draft context assessment. The context assessment was translated to Online Surveys (https://onlinesurveys.jisc.ac.uk/) and a digital wire-frame prototype of the tool was developed in the design software Penpot.⁵⁵

Figure 7. Workshop 2 paper prototyping group activity.

In Workshop 3 (online), members were guided to interact with and ‘use’ the digital prototype, including completing the context assessment digitally and giving feedback on the tools’ design, user journey, and content ( Figure 8). After Workshop 3 the prototype tool was further refined and iterated based on feedback, and the inclusion of a milestone tracker function was added. Then, for use within the scope and limits of the PASSPORT study, we translated the Penpot prototype into a useable system within the MS Office package.

Figure 8. Workshop 3 screenshot from the digital prototype.

Additionally, workshop activities and conversations informed the portfolio content, i.e. the activities that would be recommended to schools through the tool. Members helped to refine content to the six pathways (see Figure 4) and emphasised how all content needed to provide options for pupils with Special Educational Needs and Disabilities (SEND) and be adaptable to all contexts.

Portfolio content development

Alongside the development of the tool, content was required for the portfolio. To maximise the quality and relevance of this content to schools, an experienced PE teacher joined the study to lead this work and provide school PE and physical activity expertise, system understanding, and language, as well as lead intervention delivery support. Informed by the formative studies (scoping review, rapid ethnography, and school survey ( Figure 3)) and co-design process, desk research was undertaken to map out activities across the six pathways and develop the materials and resources required for a school to implement each activity. For example, for the Breaktime and Lunchtime pathway, investment in pupil leadership programmes was identified as an activity, and so the practical resources, guidance and implementation materials a school would require in order to introduce and sustain this was created, in this case a guide to developing physical activity ambassadors, template certificates to be given to them, and a catalogue of pupil leadership packages that can be purchased. For additional input and scrutiny, all draft content was reviewed by a primary PE specialist and feedback integrated.

The Consolidated Framework for Implementation Research (CFIR) was used to further strengthen the intervention content.^32,33 CFIR provides a structure to consider factors that influence implementation, including characteristics of the intervention, the school environment, external influences, individual staff factors and the processes used to support change. Using this framework helped ensure that implementation was embedded within design decisions rather than treated as a separate phase. For example, consideration of implementation climate, a CFIR construct, informed the inclusion of content focused on developing school leadership support, engaging staff and aligning physical activity with existing school and national priorities, recognising that the wider school environment would influence the feasibility and sustainability of the intervention implementation.

4. Piloting the PASSPORT intervention

To pilot and refine the PASSPORT intervention, a study was conducted with two contextually contrasting schools (inner city and suburban, differing pupil demographics, both with high indicators of disadvantage) in the Bristol area as learning partners over a seven-month period (June 2025 – December 2025). The study protocol is available.⁵⁶ This pilot was also used to test and improve plans for school and pupil recruitment, communications, and physical activity data collection for a main evaluation, and so did not aim to estimate the impact of the intervention on physical activity outcomes.

Pupil recruitment and quantitative data collection

Alongside the intervention delivery and evaluation, physical activity data were collected from pupils to monitor recruitment and retention rates, and amount of valid data. Parent consent and pupil assent was provided, along with pupil demographic information. All Year 4 pupils were eligible to participate, and physical activity data were collected via wrist-worn Axivity AX3 triaxial accelerometers worn for six days on three occasions (once at T0, T1, and T2). Pupils completed a paper questionnaire in school time which they completed twice (T0 and T2). Pupil absence data was collected for the study cohort year group (T0 and T2). Data collection in the schools was successful, and demonstrated our plans a future trial and evaluation are feasible. A total of 46 pupils were recruited at baseline from a potential total of 57 across the two schools, with high levels of data provision across the three measurement points (64–85%). At each measurement point (T0, T1, T2), two weekdays of valid accelerometer data were required to calculate a pupil’s mean weekday MVPA. Nearly all (45; 98%) pupils provided a valid weekday MVPA from at least one measurement point and over half (25; 54%) had measurements for all three. Table 3 provides school and participant demographic information, and Table 4 summarises data provision by time point.

Intervention and evaluation

Schools completed a school-study agreement to consent to the study, which included providing school demographic data. At T0 (baseline, Term 6 of the 2024–25 school year, June–July 2025), both schools completed the context assessment and received their recommended activities via the PASSPORT tool, as well as the core package resources. At T1 (Term 1 of the 2025–26 school year, September–October 2025) each school received £3,000 to spend on their bespoke programme, as well as their action plans and milestone trackers via the tool. They began delivery of their bespoke programmes which continued into T2 (Term 2, November–December 2025). A process evaluation was conducted to understand implementation and user experiences and further improve the overall intervention. Semi-structured interviews with intervention leads (in both schools this was the Head Teacher) at T0 and T2 (four interviews in total) explored experiences of using the tool and selecting their programme, delivering the programme, any successes or barriers, and key learning for us to take forward to improve the intervention. At the start of T2, schools completed an intervention implementation form to provide an update on progress, thoughts about the programme and the support given, as well as the response of the wider school staff and pupils. At the end of T2 schools completed an intervention component form to assess their bespoke programme, associated costs, and the engagement of staff and pupils.

Findings

The delivery of the intervention and use of the PASSPORT tool was well received. Quotes have been used to illustrate points in the text below. These quotes are identified by the school ID (S1, S2), data collection method (interview = I, intervention implementation form = IIF, and intervention component form = ICF), and where interviews, the interview number (I1, I2). For example, S1I2 is school 1 interview 2, or S2IIF is school 2 intervention implementation form.

Both schools made progress on the delivery of their bespoke programmes, although progress varied between the schools. The intervention implementation forms indicated that after one term of implementing their bespoke programmes (the start of T2), schools were still in the early stages, but delivery was progressing, with early engagement from pupils and staff alongside organisational and contextual factors that shaped the pace of implementation. For example, one school noted that “some staff have already begun to try […] movement breaks in classrooms,” (S1IIF), and they were in the planning stage for further activities. Several factors were highlighted that influenced early implementation and explained some difference between the schools, including competing priorities for school staff and practical challenges linked to environmental changes such as school procurement rules.

Interviews indicated that the intervention process, including completing the context assessment and using the tool to select and deliver their bespoke programme, was generally viewed as acceptable and appropriate. The context assessment was perceived as manageable and useful for reflection, with one participant noting that it “didn’t […] feel really onerous” and could help schools “reflect on where you are or what your priorities are” (S1I2). The programme selection part of the tool was also viewed positively, with one respondent describing it as “easy to use … and not overly time consuming”, adding that “it flows absolutely fine” compared with other reporting systems used in schools (S2I2). Participants spoke positively about the support provided by the research team, describing the overall process as “a very supportive process throughout” (S1I2).

Despite this, some implementation planning and support features of the tool were used less frequently than intended. Schools reported limited engagement with the action plan and milestone tracking elements because of competing demands on staff time. As one headteacher explained, “you had to spend a bit of time doing it … it [lack of engagement] was more of a time thing” (S1I2). Additionally, the intervention component forms showed mixed progress with allocating the programme budget which indicated that this could be better supported.

Participants described the activities recommended to them as practical and relevant to their school contexts, with one noting that “they were all things that could be useful” (S1ICF) and that the recommendations reflected areas where schools were already seeking to increase activity opportunities. The structured presentation of options was also viewed as helpful for decision making, with one headteacher explaining that the process helped move ideas “from just having it in your head” (S2I2) towards planned implementation. Pupils in school 1 were reported to respond positively to the opportunities for movement, and staff attitudes were generally supportive. The school reported one lunchtime activity was “very inclusive … [and] suit children with a variety of needs” (S1IIF). They explained that they saw early positive behavioural impacts from this activity, stating “lunchtime incidents have dropped dramatically and there is less [pupil] dysregulation after lunch” (S1IIF), and described it as engaged in by “many children who weren’t otherwise as active” (S1IIF).

Taken together, the responses suggest that the bespoke programme activities selected by the schools were suitable and appropriate to each school, and were integrated into existing school priorities and routines, with perceived benefits for pupil engagement and behaviour alongside increased opportunities for movement during the school day. The pilot and evaluation also brought out key learning and feedback to further develop the intervention. This included improving budget planning support in the tool at the activity selection and delivery stages, planning for an additional support meeting between the research team’s intervention delivery lead and a school to support using the action plan and milestone tracker, developing a video and information sheet to support the use of the tool, and the inclusion of questions to explore suggested areas for potential impact beyond MVPA in a future trial process evaluation, namely for pupil behaviour and attainment as well as attendance.

5. Key learning for designing context-specific public health interventions

Public health research is increasingly seeking to design complex interventions that are sensitive to different setting and community needs. This paper has outlined how the PASSPORT intervention, a school-based physical activity intervention, was developed, as a case study of designing a context-specific portfolio intervention to deliver bespoke programmes in schools. This section outlines key learning from the PASSPORT study to support putting context at the centre of public health intervention design broadly, beyond schools and physical activity. Table 5 summarises the key learning.

Ground intervention design in a range of data and insight

Grounding the intervention development in a range of data and insight generated through the formative work and co-design supported the context-specific design. However, synthesising findings from across this number of formative studies required time and a structured approach and this must be factored into plans for future studies. For example, from the outset a central research question was what was meant by ‘school context for pupil physical activity’. Initial exploration of this in the interviews, deeper exploration in the ethnography, broader insights in the school survey, and then validation of the insights in co-design, established which aspects of schools needed to be considered and included in the intervention, which communities needed to be involved, and highlighted practical design and implementation issues such as how decision-making takes place and where physical activity sits within broader school priorities. As demonstrated in Figure 3, the interconnectedness of the data and insight has been key to understanding school physical activity context. None of the formative work studies or intervention development processes alone provide the whole picture, and the strength is in their combination. For example, the breadth and depth of the formative work enabled identification of which aspects of pupil physical activity diverge across school settings and which are broadly consistent, to feed into the intervention design.⁴⁰ Designing a context-specific, and in our case flexible, intervention is complex; creating a structured approach to capture this complexity and richness is valuable.

Centre contextual experience

Centring contextual experience in the design of a context-specific intervention works to ensure it will meet user needs, be suitable and appropriate, and be more likely to work within systems and priorities. Employing user-centred design methods and processes carefully, and co-designing with school Physical Education and physical activity expertise (both within and outside of the research team), have supported the suitability of the PASSPORT tool through understanding the level of information needed to use the tool effectively, how and where content needed to be adaptable, and which broader regulatory and statutory reporting systems it could support and align with. The co-design process of the PASSPORT tool brought forward insight and design decisions that would not have been apparent otherwise. Examples of this include: understanding the context assessment could meet a current gap in primary schools as a physical activity audit tool and expanding areas school staff identified; identifying the need for the core package to support school physical activity culture and the delivery of bespoke packages; designing for activities and areas of work to start with foundations and build, allowing a school at any stage in their physical activity provision to have relevant content; the importance of adaptability for pupils with SEND; and the addition of delivery tools such as the action plan and milestone tracker. Bringing context-specific expertise within a research team developing an intervention can provide further insight and contextual implementation support. Therefore, including user-centred design methods such as ideation workshops with key stakeholders, and bringing in contextual expertise, is valuable in developing context-specific public health interventions.

Design for intervention flexibility and user autonomy

A key mechanism for making the PASSPORT intervention ‘context-specific’ was to design a process for schools to select their own bespoke intervention, i.e. schools could have choice over a bespoke intervention that would differ in each setting. Across the development of the PASSPORT intervention school communities expressed their support for this premise, having experienced resources and programmes that were not be suitable for their particular setting.³⁷ A central question throughout the intervention design was identifying where flexibility needed to be built in and the balance of autonomy and guidance that was necessary at each step. For example, in the PASSPORT intervention completed context assessments are reviewed by a school physical activity expert in the research team and recommendations provided based on it. This is a structured process to focus priorities and avoid school overwhelm, but it takes place in conjunction with a meeting to discuss the recommendations, and schools can advise if adaptations are needed. Schools are then expected to select the activities they think are most suitable and ideal for their school, and therefore have autonomy over their choice, with support from the research team. Another area where flexibility has been intentionally designed is that the structure of the tool is easily extendable to accommodate additional intervention activities or pathways as the work develops. Designing for flexibility and user autonomy, therefore, centres context in the intervention by being responsive and adaptive. Results from the pilot study are promising and indicate this approach supports staff use of the tool and a context-specific approach, however, a full trial of the intervention with process evaluation is needed to better evaluate this.

Build in processes to test and iterate

The context-specific intervention developed in the PASSPORT study involves a set of steps that alone are simple but is it essential they work together and that appropriate support is provided throughout. It is therefore helpful to build in processes and time to test and iterate the intervention, as with any intervention development process, but with attention on keeping the intervention design focused on setting context, usability, and acceptability. The ideation workshops were a structured process for this, with the aim of developing and iterating prototypes of the tool, but this was further explored by delivering and evaluating the intervention in the pilot study. Across these processes aspects of the intervention that were initially included or developed were dropped or adapted. One example is after Workshop 1 the tool paper prototypes organised intervention activities by time frame, actioned ‘this week’, ‘this term’, and ‘this year’, to break down intervention delivery into more manageable steps and deliver some ‘quick wins’. However, during Workshop 2 and in iterating the prototype afterwards it became clear this approach did not account for the immediate actions necessary to deliver longer term activities. Ultimately, this iteration and co-design led to the action plan and milestone tracker features of the PASSPORT tool. However, even with the PASSPORT study funded through development to trial, further testing and iteration would be beneficial, and therefore we recognise there are practical project limits to conducting this. This highlights that the successful design of context-specific interventions requires not just evidence-based or co-design elements, but an interactive testing process to ensure that it works in practice and meets the needs of all involved. This is particularly the case for complex interventions with multiple components or stages that need to work together.

6. Conclusion

Designing context-specific public health interventions has the potential to improve intervention success across the field. In this paper we have outlined the steps we took to design a portfolio intervention that supports schools to select and deliver tailored intervention content that would be most suitable to their setting. These steps included undertaking a range of formative studies to generate a breadth of contextual and practical insight, and then taking this insight into intervention design and content development, via co-design, embedding school expertise, and piloting. Each of these studies or steps provided useful insight and information on the setting context and for intervention design. However, combined they provide a rich and complex grounding from which to develop a non-traditional intervention approach.