1. Institute of Education, University College London, London, UK
2. Centre for the Development and Evaluation of Complex Interventions for Public Health Improvement (DECIPHer), Cardiff University, Cardiff, UK
3. Institute of Child Health, University College London, London, UK
4. Department of Medical Statistics, London School of Hygiene and Tropical Medicine, London, UK
5. Medical Research Council/Chief Scientist Office Social and Public Health Sciences, Glasgow, UK
6. Social Science Research Unit, Institute of Education, University College London, London, UK
7. Department of Health Services Research and Policy, London School of Hygiene and Tropical Medicine, London, UK
8. Department of Child and Adolescent Psychiatry, Kings College London, London, UK