Protocol for developing a core outcome set for evaluating school-based physical activity interventions in primary schools.

Introduction: Primary school-based physical activity interventions, such as The Daily Mile initiative, have the potential to increase children’s physical activity levels over time, which is associated with a variety of health benefits. Comparing interventions or combining results of several studies of a single intervention is challenging because previous studies have examined different outcomes or used different measures that are not feasible or relevant for researchers in school settings. The development and implementation of a core outcome set (COS) for primary school-based physical activity interventions would ensure outcomes important to those involved in implementing and evaluating interventions are standardized. Methods and Analysis: Our aim is to identify a Core Outcomes Set for studies of school based physical activity interventions. We will achieve this by undertaking a four-stage process: (1) identify a list of outcomes assessed in studies through a systematic review of international literature; (2) establish domains from these outcomes to produce questionnaire items; (3) prioritize outcomes through a 2-stage Delphi survey with four key stakeholder groups (researchers, public health professionals, educators and parents) where stakeholders rate the importance of each outcome on a 9-point Likert scale ( consensus that the outcomes should be included in the COS will be determined as 70% or more of all stakeholders scoring the outcome 7 to 9 and 15% or less scoring 1 to 3); (4) achieve consensus on a final Core Outcomes Set in face-to-face meetings with a sample of stakeholders and primary school children. Ethics and Dissemination: We have received ethical approval from Imperial College London (ref: 19IC5428). The results of this study will be disseminated via conference presentations/public health meetings, peer-reviewed publications and through appropriate media channels. Registration details: This study has been prospectively registered with Core Outcome Measures in Effectiveness Trials Initiative (COMET); number: 1322.SS is funded by the National Institute for Health Research for Public Health Research (NIHR SPHR). KAF and BR are funded by ‘The Daily Mile Foundation’ supported by INEOS.TV is funded by an NIHR SPHR PhD Studentship. The NIHR School for Public Health Research is a partnership between the Universities of Sheffield; Bristol; Cambridge; Imperial; and University College London; The London School for Hygiene and Tropical Medicine (LSHTM); LiLaC – a collaboration between the Universities of Liverpool and Lancaster; and Fuse - The Centre for Translational Research in Public Health a collaboration between Newcastle, Durham, Northumbria, Sunderland and Teesside Universities. EvS is supported by the Medical Research Council (MRC) (Grant MC_UU_12015/7)