1. Nuffield Department of Primary Care Health Sciences University of Oxford Oxford UK
2. Cancer Prevention and Control Program Georgetown University‐Lombardi Comprehensive Cancer Center Washington DC USA
3. Centre for Outcomes Research and Effectiveness, Research department of Clinical, Educational and Health Psychology University College London London UK
4. Addiction Research Group, Norwich Medical School University of East Anglia Norwich UK
5. Tobacco Research and Treatment Center, Department of Medicine, Massachusetts General Hospital Harvard Medical School Boston MA USA