1. Child Health Evaluative Sciences, The Hospital for Sick Children, Toronto, ON, Canada
2. Division of Biostatistics, Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
3. Department of Statistical Science, University College London, London, UK
4. School of Health and Related Research (ScHARR), University of Sheffield, Sheffield, UK
5. Centre for Health Economics, University of York, York, UK
6. Harvard Medical School & Harvard Pilgrim Health Care Institute, Harvard University, Boston, MA
7. School of Social and Community Medicine, University of Bristol, Bristol, UK
8. Stanford Health Policy, Centers for Health Policy and Primary Care and Outcomes Research, Stanford University, Stanford, CA, USA