Table 1 Proportions and mean values of variables at initial sample, and for respondent parents supplying autism spectrum disorder diagnosis data, both with and without weighting
Sample at birthIncluded in study sample at follow-up
Predictors of drop-outnnUnweightedWeighted
ALSPAC
Mother’s age at childbirth, years: mean (s.d.)14 08227.98 (6.10)276928.63 (6.31)28.25 (6.35)
Mother’s education, %
 <A-level12 3406475645860
 A-level222626
 Degree131615
Mother’s social class, non-manual: %99978064828381
Father’s social class, non-manual: %10 9045669406158
MCS
Mother’s age at childbirth, years: mean (s.d.)18 54228.32 (5.96)708228.91 (6.83)28.54 (6.81)
Mother’s education, %
 <A-level14 3435710 7465457
 A-level121212
 Degree313331
Mother’s social class, professional or intermediate: %16 3564811 9835151
Father’s social class, professional or intermediate: %12 9114399064647
  • ALSPAC, Avon Longitudinal Study of Parents and Children; MCS, Millennium Cohort Study.