1. Institute of Education, University of London; Evidence for Policy and Practice Information and Coordinating Centre (EPPI-Centre), Social Science Research Unit (SSRU); 10 Woburn Square London UK WC1H 0NR
2. University of Hertfordshire; Centre for Research in Primary and Community Care; College Lane Hatfield Hertfordshire UK AL10 9AB
3. London School of Hygiene & Tropical Medicine; Cochrane Injuries Group; Keppel Street London UK WC1E 7HT