Weighted sample characteristics
| English sample* (n=8290) | Absence sample (n=6659) | Attainment sample (n=6204) | |
| Sex, % (n) | |||
| Female | 48.8 (4105) | 49.0 (3293) | 50.2 (3139) |
| Male | 51.2 (4184) | 51.0 (3366) | 49.8 (3065) |
| Ethnic group, % (n) | |||
| Black or Black British | 3.8 (396) | 3.2 (264) | 3.2 (255) |
| Indian | 2.3 (312) | 2.0 (232) | 2.1 (224) |
| Mixed | 3.8 (312) | 3.5 (233) | 3.3 (204) |
| Pakistani and Bangladeshi | 5.6 (795) | 4.9 (585) | 5.1 (553) |
| White | 83.1 (6304) | 84.9 (5233) | 85.0 (4862) |
| Other ethnic groups | 1.5 (146) | 1.4 (112) | 1.4 (106) |
| Partnership status, % (n) | |||
| Single parent | 14.9 (1117) | 15.0 (897) | 13.5 (762) |
| Living with partner | 85.1 (7173) | 85.0 (5762) | 86.5 (5442) |
| Maternal age at birth (years), mean±SD | 28.5±5.9 | 28.3±5.9 | 28.4±5.8 |
| Maternal smoking, % (n) | |||
| Never smoked | 51.5 (4646) | 49.9 (3636) | 51.3 (3474) |
| Smoked before pregnancy but reduced/quit | 27.5 (2024) | 29.3 (1738) | 28.2 (1557) |
| Smoked during pregnancy | 6.2 (450) | 6.5 (381) | 5.9 (320) |
| Smoked in other times | 14.8 (1151) | 14.3 (904) | 14.6 (853) |
| Number of siblings | |||
| None | 42.1 (3436) | 41.9 (2573) | 41.2 (2709) |
| One | 36.2 (2924) | 36.8 (2216) | 36.8 (2381) |
| Two or more | 21.7 (1930) | 21.3 (1415) | 21.1 (1569) |
| Highest household education, % (n) | |||
| No education | 9.6 (806) | 9.4 (617) | 8.1 (511) |
| Overseas only | 2.0 (203) | 2.1 (169) | 1.9 (152) |
| NVQ level 1 | 6.2 (487) | 6.6 (412) | 6.1 (357) |
| NVQ level 2 | 25.5 (2036) | 27.6 (1780) | 27.4 (1645) |
| NVQ level 3 | 15.6 (1267) | 16.4 (1069) | 16.6 (1003) |
| NVQ level 4 | 34.8 (2919) | 33.1 (2256) | 34.7 (2185) |
| NVQ level 5 | 6.3 (571) | 4.8 (356) | 5.1 (351) |
| Household income, % (n) | |||
| Q1—Lowest income quintile | 20.8 (1750) | 21.1 (1403) | 18.9 (1191) |
| Q2 | 20.4 (1783) | 21.4 (1494) | 21.0 (1370) |
| Q3 | 20.0 (1595) | 21.3 (1375) | 22.0 (1315) |
| Q4 | 19.1 (1567) | 19.9 (1318) | 20.9 (1280) |
| Q5—Highest income quintile | 19.5 (1585) | 16.2 (1069) | 17.3 (1048) |
| Household tenure, % (n) | |||
| Own | 59.7 (5071) | 59.1 (4075) | 61.6 (3926) |
| Social rent | 25.4 (2011) | 26.2 (1635) | 24.2 (1421) |
| Private rent | 9.0 (706) | 8.9 (559) | 8.4 (495) |
| Other | 5.9 (499) | 5.9 (390) | 5.8 (362) |
| Area-level income deprivation, % (n) | |||
| Q1—Most deprived | 26.0 (2750) | 26.2 (2204) | 24.8 (1983) |
| Q2 | 21.0 (1781) | 22.4 (1524) | 22.0 (1400) |
| Q3 | 19.3 (1436) | 19.4 (1170) | 20.0 (1128) |
| Q4 | 17.2 (1156) | 16.5 (895) | 16.8 (846) |
| Q5—Least deprived | 16.5 (1142) | 15.5 (866) | 16.3 (847) |
| Birth weight in kg, mean±SD | 3.4 (0.6) | 3.4 (0.6) | 3.4 (0.6) |
| Small-for-gestational-age† | |||
| Average-for-gestational-age (>10%) | 93.5 (7499) | 93.3 (6161) | 93.5 (5754) |
| Small-for-gestational-age (≤10%) | 6.5 (595) | 6.7 (498) | 6.5 (450) |
Note: Variables were derived from Sweep 1 (age 9 months). Month of birth is not included in the table. Means and percentages are weighted using complex sample weights; frequencies are unweighted. Percentages might not add up to 100 due to rounding.
*Frequencies might not add up to total due to missing values.
†Based on INTERGROWTH-21st standards.20