1. Centre for Primary Care and Public Health, Barts and the London School of Medicine and Dentistry, London E1 2AT, UK
2. Medicines and Prescribing Centre, National Institute for Health and Clinical Excellence, Liverpool L13 1FB, UK
3. Oxfordshire Primary Care Trust, Oxford OX4 2LH, UK
4. Keele University, Keele ST5 5BG, UK
5. University of Southampton, Southampton SO17 1BJ, UK
6. North of England Specialist Commissioning Group, Warrington WA4 6HL, UK