Table 1 Correlation coefficients for the relationship of IQ at 7, 9 and 11 years with social and physical characteristics of study participants.
IQ at 7 years | IQ at 9 years | IQ at 11 years | |
---|---|---|---|
Birth weight | |||
r | 0.11 | 0.09 | 0.09 |
n | 6905 | 6803 | 6813 |
Father's social class in childhood† | |||
r | −0.31 | −0.29 | −0.31 |
n | 6905 | 6803 | 6813 |
Family size in childhood† | |||
r | −0.24 | −0.21 | −0.24 |
n | 6898 | 6774 | 6807 |
Housing tenure in childhood | |||
r | 0.24 | 0.23 | 0.22 |
n | 6873 | 6774 | 6783 |
Car ownership in childhood | |||
rpb* | 0.17 | 0.15 | 0.15 |
n | 6860 | 6760 | 6768 |
Educational attainment | |||
r | 0.52 | 0.56 | 0.61 |
n | 6812 | 6711 | 6721 |
Income in adulthood | |||
r | 0.29 | 0.30 | 0.32 |
n | 6756 | 6656 | 6667 |
Social class in adulthood† | |||
r | −0.40 | −0.43 | −0.46 |
n | 6752 | 6657 | 6672 |
Housing tenure in adulthood | |||
r | 0.23 | 0.22 | 0.24 |
n | 6895 | 6793 | 6803 |
Car ownership in adulthood | |||
r | 0.21 | 0.19 | 0.19 |
n | 6892 | 6790 | 6768 |
*Point biserial correlation coefficient.
†Higher scores on these variables indicates greater socioeconomic adversity.
For all correlation coefficients, p<0.001.