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The Predictors and Consequences of Early Parenthood. PhD Student: Dylan Kneale Supervisors: Professor Heather Joshi & Dr Jane Elliott Centre for Longitudinal Studies, Institute of Education, University of London. Background. UK demography witness to decreasing fertility rates.
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The Predictors and Consequences of Early Parenthood PhD Student: Dylan Kneale Supervisors: Professor Heather Joshi & Dr Jane Elliott Centre for Longitudinal Studies, Institute of Education, University of London
Background • UK demography witness to decreasing fertility rates. • Age at first birth consistently increasing – in just 15 years, between 1985 and 2000, the age at first birth rose from 25.9 to 29.1 years¹. • One of a set of demographic changes characteristic of the ‘Second Demographic Transition’ (SDT) • A number of explanatory theories for demographic transition that revolve around either economic or cultural change or both. • Particular recent interest in young age at first birth as it is a recognised marker of disadvantage. • However, confusion if young age at first birth purely a marker of existing disadvantage (Geronimus 2003; Goodman 2004) or a cause of future disadvantage (SEU 1999). ¹United Nations Economic Commission for Europe 2002
Background Chart 1: Age at first birth and household income (Age 16) Chart 2: Age at first birth and household income (Age 46)
Background • In line with these theories, the timing of parenthood can be viewed as an economic and cultural adaptation to local circumstances. • A wide body of evidence exists on the predictors of early motherhood. Less interest in the timing of fatherhood. • Known predictors include educational attainment, socioeconomic measures of family background and personal characteristics among others. • However, according to some demographic theories, contextual influence is highly significant in the timing of parenthood, although this area comparatively unexplored.
Research Questions • When should parenthood be thought of as being early? • How many people experience early parenthood? • What are the factors that predict early parenthood? • To what extent do contextual factors predict early parenthood? • Do these contextual factors affect the outcomes of parents and children?
Data Utilise strengths of the birth cohort studies to examine factors affecting fertility. • National Child Development Study (NCDS) – Originally included all live births in G.B from one month in 1958. • British Cohort Study (BCS70) – Originally included all live births in U.K from one month in 1970. • In both studies, the addition of immigrants has been offset by attrition:
Data Collection NCDS 1974 NCDS (Age 16) 1965 NCDS (Age 7) 1991 NCDS (Age 33) 2004 NCDS (Age 46) 1969 NCDS (Age 11) 1981 NCDS (Age 23) 1958 NCDS Birth 2000 NCDS (Age 42) 1975 BCS70 (Age 5) 1986 BCS70 (Age 16) 2000 BCS70 (Age 30) 1980 BCS70 (Age 10) 1996 BCS70 (Age 26) 1970 BCS70 Birth 2004 BCS70 (Age 34) Data Collection BCS70
What is early parenthood? • Early parenthood synonymous with teenage parenthood in media • Is this meaningful distinction or just convention? • Age specific fertility rate for teenagers decreased from 30 births per 1000 women in 1985 to 26 births per 1000 in 2005 (ONS) • Is focus reactive to media and political constructions or real differences?
How should early parenthood be defined? • Using absolute cut off points, survival analysis and piecewise regression to derive definitions of early parenthood: • The literature supports the idea that the effects of the timing of parenthood are felt up to a certain point, changing after this. Piecewise regression methods are used to test this proposition.
How should early parenthood be defined – example output….. • In the above output, a spline has been identified at age 32. Up to this age, delaying fatherhood corresponds to an increase in household income of value age1 (However, other factors do mitigate the relationship) • Age2 corresponds to the value of the difference between slopes up to 32 years and ages afterwards – significantly different
How could early fatherhood be defined? 27 years spline identified from NCDS cm’s mother’s age at first birth 21 years 2 months, first 12.5% of NCDS cohort are fathers 24 years 11 months, first 25% of NCDS cohort are fathers 32 years spline identified from NCDS income 14 years 5 months, first NCDS father Teenage Birth 15 years 2 months, first BCS70 father 23 years 11 months, first 12.5% of BCS70 cohort are fathers 27 years, first 25% of BCS70 cohort are fathers 28 years spline identified from NCDS test scores Conclusion: Teenage definition is a poor definition of early fatherhood. Given the data, a proportional definition is satisfactory
How could early motherhood be defined? 22 years 2 months, first 25% of NCDS cohort are mothers 27 years spline identified from NCDS cm’s mother’s age at first birth 19 years 11 months, first 12.5% of NCDS cohort are mothers 33 years spline identified from NCDS income 13 years 2 months, first NCDS mother Teenage Birth 23 years 11 months, first 25% of BCS70 cohort are mothers 15 years 2 months, first BCS70 mother 20 years 8 months, first 12.5% of BCS70 cohort are mothers 28 years spline identified from NCDS test scores Conclusion: Teenage definition is a poor definition of early motherhood. Given the data, a proportional definition is satisfactory
However, both studies have suffered from attrition – how representative are the cohort fertility patterns with other sources?
How many early parents feature in NCDS and BCS70? – the definitions to be used in the remainder of the research….
What do we know about the predictors of early parenthood? • Know from the literature that socioeconomic, educational, demographic and personal variables are significant predictors of the timing of parenthood in addition to contextual effect. • These variables will form controls in models that test the residual contextual effects • Neighbourhood data available as census variables with diverse indicators such as % married women working and % with indoor bathroom at 2 levels of geography Contextual Factors Individual Factors Timing of Motherhood
Neighbourhood factors as predictors of early parenthood (I) • Due to the nature of the birth cohort studies, no complex modelling needed to capture neighbourhood effects in BCS70 and NCDS (such as MLM). Models below could be used with inclusion of individual level measure to avoid ecological fallacy HOWEVER…….
Neighbourhood factors as predictors of early parenthood (II) Despite limitations, after controlling for known confounders and individual measurements, some conclusions can be drawn: • Neighbourhood found to exert a small but significant effect on fertility • Some more cultural measures of neighbourhood such as % of immigrants; % of population aged 0-4 years and % of married women working highly insignificant. • In general, neighbourhood effects appear to exert a stronger influence on the timing of fatherhood than motherhood, although significant results found for the timing of motherhood • Social class measurements on the local authority level more likely to influence the timing of fatherhood • Tenure measurements on the enumeration district level more likely to influence the timing of motherhood • Some indication of gender-occupation interactions found with certain variables (e.g. % of workforce in mining and manufacturing)
Neighbourhood factors as predictors of early parenthood (III)
Other Contextual factors as predictors of early parenthood Because of the limitations in exploring neighbourhood (census) variables further, a broader definition of context adopted will be adopted. In particular this will explore the concept of resilience by looking at the environment provided by parents not directly associated with socioeconomic factors. Preliminary work into parental interest in education reveals this to be significant predictor of fertility patterns net of socioeconomic factors. A number of measures of family life remain unexplored.
Future Directions Immediate: • Conclude neighbourhood measurements section and change modelling strategy for the timing of parenthood (survival) variables: theoretically and empirically problematic. • Continue exploratory analysis of parental environment variables and explore their significance as predictors. Mid-term: • Decide on final modelling strategies for predictors • Conclude the effects of contextual factors on the timing of parenthood Long-term: • Begin to examine the effects of these contextual factors and interactions with age at first parenthood on the outcomes of mothers and children