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Educational Attainment, Labour Market Conditions and the Timing of First and Higher-Order Births in Britain. Andrew Jenkins, Heather Joshi & Mark Killingsworth EALE Conference, Amsterdam, Sept 2008. Research: Aims. Compare timing of births in two British cohorts
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Educational Attainment, Labour Market Conditions and the Timing of First and Higher-Order Births in Britain Andrew Jenkins, Heather Joshi & Mark Killingsworth EALE Conference, Amsterdam, Sept 2008
Research: Aims • Compare timing of births in two British cohorts • How is timing of births influenced by education level? • How is timing of births influenced by labour market conditions – specifically aggregate unemployment? • Check sensitivity of results to unobserved heterogeneity
British Cohort Datasets • National Child Development Study (NCDS) • women from a cohort born in a particular week in March 1958 • combine birth history data from 1991, 2000 and 2004 sweeps • British Cohort Study (BCS70) • women from a cohort born in a particular week in April 1970 • combine birth history data from 2000 and 2004 sweeps
Survival Curves for First Birth by Education LevelNCDS (1958 cohort) BCS (1970 cohort)
Method (1): • Investigate time to first three births • Use hazard models (event history models) • education and lagged unemployment as explanatory variables • Other variables in model include: age 11 ability test scores, free school meals (age 11), Father’s SES, mother’s education, religion, number of siblings
Method (2): • Continuous time hazard model estimated in CTM • Estimate: where h is the hazard; t is duration in state i before exiting to state j; X is a vector of explanatory variables; θ is person-specific unobserved heterogeneity • θij = fijθ • Use non-parametric specification of heterogeneity
Results for EducationHazard model jointly estimated for first three births
Results for UnemploymentHazard model jointly estimated for first three births
Results: Heterogeneity • Allowing for unobserved heterogeneity: • Improvement in fit of models • Results for both education and unemployment sensitive to the inclusion of heterogeneity terms
Conclusions • Results consistent with interpretation of education as a causal influence on fertility (time to first birth) • Results for aggregate unemployment: negative effect on 1st birth, significant only for 1970 cohort • Important to control for unobserved heterogeneity in modelling times to first and higher order births