Developing a theory of change, outcome measures and evaluation design for an evaluation of the impact of the Daily Mile on obesity and health

Getting children to be more physically active is important. Many do not currently do enough exercise to protect their health. This contributes to the growing problem of obesity. To address these problems, the UK Obesity Strategy has many recommendations: one is that primary schools take part in The Daily Mile. This involves children running or walking/jogging for 15 minutes every day, in school, in which time most children will average at least one mile in distance. It is a popular scheme which started in Scotland and is now being rolled out widely, with over 750 schools in England already taking part. There are many potential health benefits from The Daily Mile. If it increases the physical activity children do, it improves their fitness and may help protect from obesity and other health problems in later life. The physical benefits may also improve children's concentration and behaviour in the classroom. However, there are also some potential negative effects. The scheme may take school time away from other, more beneficial, activities. It may put some children off doing sports or other activity in later years. We would like to understand more about all the possible health effects from the Daily Mile, and (if these are positive) how it works best. What is needed for it to work? What stops it working? Does it have different effects for different kinds of children or schools?
These are difficult questions to answer because we cannot just compare children who have taken part with those who haven't. Schools that choose to take part are likely to be different from the ones that don't, and health differences we find may reflect this, not the effect of The Daily Mile. This is a common problem in public health research. An additional problem is that policy makers need to know whether a scheme will work in their area. Schools will want information on what the necessary conditions for success are, and how to implement the scheme to get the most benefit.

We aim to look at all the possible ways that The Daily Mile might impact on children's health. We are particularly interested in obesity. All children are weighed and measured at age 5/6 and again at age 10/11, so we can compare differences in weights over time within schools which have and have not taken part. We also want to find out what other possible outcomes might be included in a study, and whether there is available information about these. Finally, we aim to develop new ways of using case studies of implementation. We will look in detail at Lewisham, talking to children, teachers, parents, heads, and public health specialists to look at what happens when a school decides to get involved in The Daily Mile. This is important because policies are taken up in complex, and varied, settings. We need to understand better how these settings affect whether something works, for whom, and why. Issues such as who decides the school will take part; what kind of school it is; what kinds of children are enrolled at the school might change what happens. We will use this information to help us understand whether The Daily Mile might have different effects for different children - such as for boys and girls, or those from different backgrounds. At the end of this study, we will have: 1) A detailed description of The Daily Mile, using a checklist used by public health researches to describe interventions; 2) A full map of all the possible health outcomes from The Daily Mile; 3) A plan for a study that can evaluate these across England. We are working in collaboration with partners who have an interest in what works to improve children's health.These include colleagues from The Daily Mile Foundation, public health specialists from Lewisham, teachers, governors and parents from schools in Lewisham and other areas, and other academic colleagues. This partnership will ensure that our findings are taken to the next stage, which will be a national evaluation of The Daily Mile.

The Daily Mile (TDM) is designed to get schoolchildren running for 15 minutes per day. It has proved acceptable to schools, with significant health benefits claimed. However, to date there have been no robust evaluations of its public health effectiveness. This represents an excellent opportunity for developing urgently-needed methodologies for evaluations of complex interventions in 'real life' settings. TDM is being implemented in a range of school settings, and usually as part of a range of broader measures: in Lewisham, for instance, within a Whole System approach. This presents evaluation challenges: identifying what 'the intervention' is; identifying effective intervention components; identifying what the necessary and sufficient conditions might be for it to have effects; identifying how these components relate to system-level change. We aim to first develop the DM as a public health intervention. We will map the scheme to the TIDieR checklist; develop a logic model to describe the theoretical pathways from intervention to outcomes, describe the full range of potential health outcomes, and identify potential costs. Second, we will develop urgently-needed methodologies for evaluating complex interventions in complex systems. Specifically, we aim to design an evaluation which combines quantitative analysis of secondary data sets (primarily BMI measures) with qualitative rapid ethnography within a quasi-experimental design. We will assess the feasibility of using Qualitative Comparative Analysis (QCA) (a mixed method approach that uses data about 'cases' - in our example schools - as well as variables) to investigate causality in complex systems. We will assess whether rapid appraisal techniques generate sufficient qualitative knowledge for a QCA. This early phase study will therefore inform an evaluation of: 1) the impact of TDM on participating children's health; and 2) the sufficient and necessary conditions for positive impact on public health.

Sedentarism and obesity are major public health issues. The ultimate beneficiaries of this research are the children who would benefit from evidence based public health measures to increase physical activity and (in the longer term) reduce obesity. The pathway from basic research such as this to final health benefit is long: we would anticipate following this early phase study with an evaluation of The Daily Mile if this is feasible: should this demonstrate positive and cost effective public health gain, the scheme can be heavily promoted by local authority Health and Wellbeing boards as a component of effective strategies for public health, with our findings on what is needed to implement The Daily Mile successfully. Should we find that there is no evidence for public health gain, or that this requires particular conditions, alternative strategies can be advocated. The pathway to achieve this gain is through publishing high quality evidence in peer-reviewed journals, where it can become in time incorporated in NICE guidance and other evidence reviews.

In the medium and shorter term, schools and The Daily Mile Foundation will benefit from our progress on developing understanding of what is needed for The Daily Mile to have effects, and refining the necessary and sufficient conditions for it to be implemented as intended. These stakeholders will also benefit from our contributions to raising awareness of the importance of physical exercise, and importance of evaluating interventions. Should our full evaluation demonstrate that TDM is effective in reducing obesity or having other positive health outcomes, The Daily Mile Foundation will gain considerable benefit, as they have informed us of frequent requests for evidence of it 'working'. Such evidence will also be useful for the range of other statutory public health stakeholders (PHE and other national organisations, local authority departments) requiring evidence of effectiveness and case study material to illustrate the benefits of physical activity, and for children in the UK and beyond as findings will be used to promote and grow the adoption of the initiative.

Participating children will benefit directly. Our past experience of working in schools suggests a large number of spin off benefits are potentially derived by the children involved, from raising awareness of science and research, to providing opportunities for children to develop skills in deliberation and consultation on issues such as how to promote physical activity.

There are also direct beneficiaries through the pathway of including research in the teaching of the applications. Apart from general use of this as a case study in Master's modules, we intend a specific benefit for the KCL MBBS students. They all elect to do a self-directed scholarly project, with mentorship from academic staff. We will offer two based on this study. One will involve a literature review on the factors that facilitate and inhibit children's enjoyment of physical activity in school settings; one involving 'peer interviews' with other medical students about their levels of physical activity and the role school based activities play in their current attitudes.