Table 3. Description of NCDS variables used in the analysis.

chrtid	Unique child (individual) identifier
fammove	Number of family moves since child’s birth (from 0 to 9)
readtest	Childhood reading test score at 7 years (from 0 to 35, high is good)
bsag	Behavioural score (from 0 to 70, high indicates more behavioural problems at 7 years)
sex	Child’s sex (0 – boy; 1 – girl)
care	In care before 7 years old (0 – no; 1 – yes)
soch7	In social housing before 7 years old (0 – no; 1 – yes)
invbwt mo_age	inverse of birthweight (ounces) Mother’s age at child’s birth (centred at 28 years)
mo_agesq noqual2	Square of mo_age Binary variable, child has no qualifications at 23 years of age (0 – at least 1 qualification; 1 – no qualifications)
agehous agesqhous	Interaction: mo_age× soch7 Interaction: mo_agesq× soch7