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

Information available on the samples of women N% NCDS women (1958 cohort) Complete birth history to age Complete birth history to age Complete birth history to age 464, TOTAL5, BCS women (1970 cohort) Complete birth history to age 29/ Complete birth history to age 344, TOTAL5,

Proportion with first birth by age 25

Education Levels

Survival Curves for First Birth by Education Level NCDS (1958 cohort) BCS (1970 cohort)

Claimant Count Unemployment Rate - Men

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 θ ij = f ij θ Use non-parametric specification of heterogeneity

Results for Education Hazard model jointly estimated for first three births First birthSecond birth NCDS (1958 cohort). Education, base category = low Medium (0.046) (0.105) (0.047) (0.055) High (0.059) (0.150) (0.056) (0.066) BCS (1970 cohort). Education, base category = low Medium (0.040) (0.060) (0.051) (0.059) High (0.054) (0.077) (0.065) (0.077) Controls for heterogeneityNoYesNoYes Control variables: all; heterogeneity controls non-parametric; standard errors in parentheses

Results for Unemployment Hazard model jointly estimated for first three births First birthSecond birth NCDS (1958 cohort) Lagged unemployment (0.007) (0.008) (0.005) (0.007) BCS (1970 cohort) Lagged unemployment (0.009) (0.009) (0.007) (0.009) Controls for heterogeneityNoYesNoYes Control variables: all; heterogeneity controls non-parametric specification; standard errors in parentheses

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 1 st birth, significant only for 1970 cohort Important to control for unobserved heterogeneity in modelling times to first and higher order births