1. PhD student, Biostatistics and Research Methods Centre, Dental Institute, King's College London, London, UK.
2. Lecturer in Statistics and Epidemiology, Department of Palliative Care, Policy & Rehabilitation, Cecily Saunders Institute, King's College London, London, UK.
3. Senior Lecturer, Division of Population and Patient Health, King's College London Dental Institute, London, UK.
4. Principal Research Fellow, University of Warwick, Warwick Medical School, Division of Health Sciences, Populations, Evidence and Technologies Group, Warwick Evidence, Coventry, UK.
5. Professor, Biostatistics and Research Methods Centre, Dental Institute, King's College London, London, UK.