1. Manchester Centre for Health Economics, University of Manchester, 4.305 Jean McFarlane Building, Oxford Road, Manchester M13 9PL, UK
2. Alliance Manchester Business School, University of Manchester, Booth Street West, Manchester M15 6PB, UK
3. Health Organisation, Policy and Economics, Division of Population Health, Health Services Research & Primary Care, Williamson Building, Oxford Road, University of Manchester, Manchester M13 9QQ, UK