1. Health Services Research Unit, University of Aberdeen, Aberdeen, UK
2. Medical Statistics Team, University of Aberdeen, Aberdeen, UK
3. Centre for Statistics in Medicine, University of Oxford, Oxford, UK
4. Department of General Practice, National University of Ireland, Galway, Ireland
5. Population Health, University of Aberdeen, Aberdeen, UK
6. Faculty of Medicine and Health Sciences, University of East Anglia, Norwich, UK
7. Health Economics and Health Technology Assessment, University of Glasgow, Glasgow, UK
8. Ottawa Hospital Research Institute, Ontario, Canada
9. Robertson Centre for Biostatistics, University of Glasgow, Glasgow, UK
10. Institute of Health and Society, Newcastle University, Newcastle upon Tyne, UK