Hayley A Hutchings1
, Penney Upton2
, Wai-Yee Cheung1
, Alison Maddocks3
, Christine Eiser4
, John G Williams1
, Ian T Russell5
, Sonia Jackson6
and Meriel EM Jenney7 
1
School of Medicine, Swansea University, Swansea, UK
2
Institute of Health, Social Care and Psychology, University of Worcester, Worcester, UK
3
National Public Health Services for Wales, Carmarthen, UK
4
Child and Family Research Group, Department of Psychology, University of Sheffield, Sheffield, UK
5
Institute for Medical and Social Care Research, University of Wales Bangor, Bangor, UK
6
Thomas Coram Research Unit, Institute of Education, University of London, London, UK
7
Department of Child Health, Cardiff and Vale NHS Trust, Cardiff, UK