1. School of Social and Political Science, University of Edinburgh , 15a George Square , Edinburgh EH8 9LD, UK
2. Department of Social Work, Monash University , Caulfield East , P.O. Box 197, Victoria 3145, Australia
3. Centre for Health Equity, Melbourne School of Population and Global Health, University of Melbourne , 207 Bouverie Street , Carlton 3053, Australia
4. Trinity Research in Childhood Centre, Trinity College Dublin, University of Dublin , 30 Anglesea Street , Dublin D02 T253, Ireland