Presentation on theme: "The Relationship between Childbearing and Transitions from Marriage and Cohabitation in Britain Fiona Steele 1, Constantinos Kallis 2, Harvey Goldstein."— Presentation transcript:
The Relationship between Childbearing and Transitions from Marriage and Cohabitation in Britain Fiona Steele 1, Constantinos Kallis 2, Harvey Goldstein 1 and Heather Joshi 3 1 University of Bristol, 2 LSHTM, 3 Institute of Education
2 Research Questions What is the link between partnership (marriage or cohabitation) stability and childbearing? –Allow for joint determination of partnership and fertility processes –Consider effects of presence and characteristics of children and pregnancy
3 Key Findings from Previous Research Having children together lowers the risk of dissolution for married couples, but there is little evidence of an effect among cohabitees Among cohabitees, having children is associated with decreased odds of marriage in GB and Canada, but increased odds in US (Manning & Smock). Sharp increase in odds of marriage during pregnancy
4 Endogeneity of Prior Fertility Outcomes Interested in effect of presence of children on partnership transitions. But children are prior outcomes of a potentially correlated process (fertility). There may be factors (some unobserved) which influence decisions about partnership transitions and childbearing. If ignored, estimates of effects of interest will be biased.
5 Methodology used in Previous British Studies Most consider 1 st partnership only –Those using NCDS look at transitions for ages 16-33 (e.g. Kiernan & Cherlin 1999; Berrington 2001) Transitions from marriage and (unmarried) cohabitation usually modelled separately Prior fertility outcomes usually treated as exogenous
6 Our Methodological Approach Consider all partnerships for ages 16-42 using multilevel modelling Estimate simultaneously models for 3 types of partnership transition: –Marriage Separation –Cohabitation Separation; Cohabitation Marriage Estimate these transitions jointly with model for fertility to allow for potential endogeneity of fertility outcomes
7 Joint Modelling of Partnership Transitions and Fertility Our research builds on US study (Lillard & Waite 1993) which used a multiprocess model to allow for possibility that the processes of divorce and childbearing are jointly determined –BUT only marital unions were considered We extend their approach to include outcomes of cohabiting partnerships Another British study (Aassve et al. 2006) also models union dissolution and fertility jointly, but groups together marriage and cohabitation. Recent US studies combine cohabitation and single
8 Methodology: Overview Multilevel data structure: repeated partnerships and births (level 1) within individuals (level 2). Use multilevel multistate discrete-time event history model (Steele et al. 2004) for partnership transitions. –States are marriage and cohabitation – Competing risks from cohabiting state Estimate jointly with model for conceptions within partnerships using simultaneous equation (multiprocess) model (extending Lillard (1993) who considers only marriage).
9 Multilevel Modelling Some women have > 1 partnership and/or conception –May be unobserved characteristics which influence risk of all partnership transitions/births –Leading to correlation between durations of partnerships/birth intervals for the same woman In a multilevel model, include random effects for each type of transition. These represent unobserved time- constant variables Correlation between random effects for different transitions are of substantive interest
10 Multiprocess Model of Partnership Transitions and Fertility Probability of partnership transition at time t Probability of conception at time t Children conceived before t X P (t) (Observed) X F (t) (Observed) u F (Unobserved) u P (Unobserved)
11 Data 1958 British birth cohort (National Child Development Study): –Partnership (living together for >1 month) and birth histories collected retrospectively at ages 33 and 42. Linked to form history for age 16-42. –Covariates from childhood and adulthood. Analysis sample: n=5142 women with 1 partner by age 42; n=7032 partnerships and n=9137 partnership episodes.
12 Measures of Prior Fertility (All Time-Varying) Current pregnancy status Number of preschool and older children living with respondent Distinguish between children fathered by current and previous co-resident partners, and those from non co-resident relationships
13 Other Explanatory Variables Previously married/cohabited Age at start of partnership Partnership duration No. years of education (time-varying) Paternal social class Family disruption before age 16 Region of residence at birth Housing tenure at birth
14 Years to Partnership Transition: Quartiles 25%50%75% Marriage Separation 12.0-- Cohab Separation 3.58.3- Cohab Marriage 184.108.40.206
15 Cross-Process Residual Correlations (* denotes significance at 5% level) Separation from marriage and marital conception r = -0.07 (-0.28* before accounting for current pregnancy) Separation from marriage and cohabiting conception r = 0.42* Separation from cohabitation and cohabiting conception r = 0.32* Cohabitation to marriage and cohabiting conception r = 0.30* (0.43* before accounting for current pregnancy)
16 Effects of Fertility Variables on Log- odds of Marital Separation
17 Effects of Fertility Variables on Log-odds of Separation vs. Staying Cohabiting
18 Effects of Fertility Variables on Log-odds of Marriage vs. Staying Cohabiting
19 Further Work Under Research Methods Project Comparison of effects of having children on cohabitation outcomes for 1958 and 1970 birth cohorts Effect of having children on partnership formation and outcomes for 1970 cohort
20 Cohort Comparisons for Cohabitation Outcomes (1958 and 1970 cohorts, age 16-30) Sharp fall in proportion legalising cohabitation during pregnancy In 1970 cohort only, evidence of stabilising effect of having children together (lower risk of dissolution) But having school-age child from previous partnership reduces odds of marriage in 1970 cohort
21 Effects of Fertility on Partnership Formation (1970 cohort, age 16-30) Pregnancy hastens cohabitation and marriage among single women Presence of preschool child from previous partnership inhibits cohabitation among single women Presence of a school-age child from previous partnership inhibits marriage (among both single and cohabiting women)
22 Publications Steele, F., Kallis, C., Goldstein, H. and Joshi, H. (2005) The Relationship between Childbearing and Transitions from Marriage and Cohabitation in Britain, Demography, 42: 647- 673. Steele, F., Joshi, H., Kallis, C. and Goldstein, H. (2006) Changing Compatibility of Cohabitation and Childbearing between Young British Women born in 1958 and 1970, Population Studies 60(2): 137-152. Steele, F., Kallis, C. and Joshi, H. (2006) The Formation and Outcomes of Cohabiting and Marital Partnerships in Early Adulthood: The Role of Previous Partnership Experience, Journal of the Royal Statistical Society, Series A 169(4): 757- 779.