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
Date of Birth  P:SDV  P:SDV
Education level  P:SDVM F/P  P:SDVM F/P P:SDVM F/P
Employment P:SDVM F/P P:SDVM F/P P:SDVM F/P
Ethnicity P:SDVM F/P P:SDVM F/P
Income P:SDV P:SDV
Language spoken at home P:SDV P:SDV
Living arrangements P:SDVM C S P:SDVC P:SDVM F/P C 
Family structure P:SDV P:SDV
Marital/relationship status P:SDVM F/P P:SDVM F/P
Occupation P:SDVM F/P P:SDVM F/P P:SDVM F/P
Siblings P:SDV P:SDV
Sex P:SDV P:SDV P: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 Devised Variable