1. MRC CTU at UCL, Institute of Clinical Trials and Methodology, University College London, London, UK
2. Department of Primary Care and Population Health, University College London, London, UK
3. Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
4. Clinical Trials Research Unit, Leeds Institute of Clinical Trials Research, University of Leeds, Leeds, UK
5. Health Services Research Unit, University of Aberdeen, Aberdeen, UK
6. UCL Institute of Education, University College London, London, UK
7. London School of Hygiene & Tropical Medicine, London, UK