Year 2001-2003 2001-2003 2003-2005 2006-2008 2008-2010
Wave 1 1 2 3 4
Age full term preterm 2 years CA 5 years CA 7 years CA
Apgar O O
Birth weight O O
Delivery O:SDV O:SDV
Drug treatments in hospital O:SDV
Dubowitz assessment O:DUBOWITZ
Due date O:SDV O:SDV
Gestational age/prematurity O:SDV
Hospital stay O:SDV O:SDV
Maternal age (at birth) O:SDV O:SDV P:SDVM  P:SDVM 
Multiple births O:SDV O:SDV
Narcotics O:SDV O:SDV
NEC (necrotising enterocolitis) O:SDV
NNNS (NICU network neurobehaviour scale) O:NNNS
Oxygen information O:SDV
Postnatal steroids O:SDV
Sepsis O:SDV O:SDV
SGA (small for gestational age) O:SDV
Ventilation O:SDV
Zygosity O:SDV
CA = Corrected age for prematurity

S – self report
P – parent report
C – child report
T – teacher report
N – welfare nurse
O – observation

XM: Mother
XF/P: Father/partner
XC: Child
XS: Sibling
XG: Grandparent

SDV: Study Derived Variable
DUBOWITZ: Dubowitz assessment
NNNS: NICU Network Neurobehaviour Scale