1. Manchester Centre for Health Psychology, University of Manchester, Manchester, UK
2. Department of Medical Statistics, London School of Hygiene and Tropical Medicine, London, UK
3. Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK
4. School of Population Health and Environmental Sciences, King’s College London, London, UK
5. Health Services Research Unit, University of Aberdeen, Aberdeen, UK
6. Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
7. Department of Health Sciences, University of York, York, UK