1. Institute of Health & Society, Newcastle University, Baddiley Clark Building, Richardson Road, Newcastle Upon Tyne, UK
2. School of Health and Related Research, Health Economics and Decision Science, The University of Sheffield, Regent Court, 30 Regent Street, Sheffield, UK
3. Nuffield Department of Population Health, University of Oxford, UK
4. Centre for Health Services Studies, University of Kent, Canterbury, Kent, UK
5. Newcastle & North Tyneside Addictions Service, Plummer Court, Carliol Place, Newcastle upon Tyne, UK
6. School of Social and Community Medicine, University of Bristol, Canynge Hall, 39 Whatley Road, Bristol, UK
7. School of Health and Social Care, Teesside University, Middlesbrough, UK
8. Economics Division, Leeds University Business School, Leeds, UK