Year ≥ 2011 ≥ 2012 ≥ 2014
Wave 1 – Enrolment 2 – Assessment (researcher home visit) plus 5-7 year questionnaires (see Wave 1 for content) 3 – Assessment (researcher home visit) plus 9-12 year questionnaires (see Wave 1 for content)
Age 1-12 months 13-24 months 2-4 years 5-7 years 8-12 years Enrolment supplement (from 13 months) 5-7 years 9-12 years
Gestational age/prematurity P:SDV P:SDV
Delivery mode P:SDV P:SDV
Multiple births P:SDV P:SDV
Length of hospital stay P:SDV P:SDV
Neonatal intensive care P:SDV P:SDV

P – Primary caregiver report
P:XXR – Primary caregiver report pertaining to primary caregiver
P:XXP – Primary caregiver report pertaining to primary caregiver’s partner
P:XXC – Primary caregiver report pertaining to child
P:XXFAM – Primary caregiver report pertaining to family
P:XXS – Primary caregiver report pertaining to siblings
S:XXC – Self report by child
O – Observation/direct assessment

SDV: Study Devised Variable