Our pilot intervention was trialled in Torfaen and Caerphilly in October 2023 and January 2024 respectively. A total of six schools trialled SMCMIM. Given the complexity of intervention design, we expected initial challenges. We tested SMCMIM in Torfaen first, intending to incorporate early insights into the subsequent pilot in Caerphilly.

Can the opt-out measure drive uptake alone?

Our prototyping workshops with parents and children highlighted that clear communication and advocacy for school food were crucial for building trust in school meals. Parents wanted to taste and see for themselves that school meals were both tasty, nutritious and satisfying. Children themselves were also eager for a taste-and-see approach.

We, therefore, tested whether simply requiring parents to opt-out if their child would not be eating a school meal was enough or if additional activities, in the form of tasting events and extra communications, would also be necessary. With this in mind, we varied the materials and activities across schools. Some changed to opt-out of school meals solely (accompanied only by rudimentary communication to announce SMCMIM to parents and children), while others were given supporting activities: these activities included tasting events for parents and children during and outside school and a letter to parents from the catering team’s dietician.

In the Caerphilly trial, we included one additional school which held a taster session for parents and children but did not take part in SMCMIM in order to understand if the taster sessions in and of themselves had an impact on increasing school meal uptake.

By comparing school meal uptake between these and non-participating schools in the same council area, we sought to understand the driving factors behind any uptake change.

Outcome measurement and process evaluation

We evaluated the intervention using quantitative and qualitative methods. Our goal was to understand how effective the intervention had been in increasing school meal uptake and to gather feedback on its execution and perceived value. We also wanted to learn how the intervention could be improved. Through a combination of data analysis and stakeholder input, we aimed to uncover the strengths and weaknesses of the intervention, ensuring a multiplicity of voices within the local school system was considered.

School meal uptake data analysis

We analysed school meal uptake data to understand if SMCMIM leads to an increase in uptake compared with non-participating schools in the area, both during and three months after SMCMIM. As this was a pilot and not statistically powered, the analysis of this data was descriptive with no inferential statistical tests being performed.

Observations and interviews during the intervention

We observed school lunchtimes during the intervention and conducted semi-structured interviews with the school and catering staff as well as pupils to assess implementation and identify challenges and strategies to overcome them. We also engaged parents in informal discussions at the school gates.

Parent survey and focus groups

A post-intervention survey and workshop invitation was sent to the parents of the approximate 1,600 pupils that attend the six schools that participated in SMCMIM. The survey and workshops aimed to help us understand why parents chose to opt out, what they liked about SMCMIM and what could be improved. Nearly 350 parents/carers responded to the survey and over 40 parents/carers took part in the workshops.

Post-intervention workshop with schools and councils

After the intervention, we organised structured workshops involving council catering leaders and the headteachers who spearheaded SMCMIM within their respective organisations. These sessions aimed to gather insights into their perspectives on the pilot's execution, identify areas for improvement, and explore possibilities for scaling the intervention.