Introducing new interventions – activities or programmes – in schools offers a great opportunity to increase children’s physical activity, but most attempts to do this have not succeeded. We argue that this is partly because traditional approaches have ignored the school context. This includes the school setting, facilities, and existing physical activity provision as well as the school culture, expertise and interests of staff, and pupil background. These can all affect the way in which programmes are designed, carried out, and tested.

Instead of trying to design a programme that will be implemented in exactly the same way in every school, in the PASSPORT study we are using a ‘context-specific’ approach to design an intervention to increase children’s physical activity in schools that puts school context at the centre.

School context is also important when it comes to testing these programmes to see if they work. This more complex approach needs a more complex evaluation, so we are designing a ‘stepped-wedge’ trial. In the stepped-wedge approach, every school in the trial will use the tool and have an intervention, and we’ll measure how children’s physical activity changes before the trial and across a year.