Union dynamics and fertility

Eva Beaujouan, Wittgenstein Centre (IIASA, VID/ÖAW, WU)
Maria Winkler-Dworak, Wittgenstein Centre (IIASA, VID/ÖAW, WU)
Paola DiGiulio, Wittgenstein Centre (IIASA, VID/ÖAW, WU)
Martin Spielauer, Statistics Canada

The link between partnership instability and fertility is increasingly explored. How cohort completed fertility is affected by new partnership behaviours and how this has changed over time is however rarely studied. In an environment where cohabitation becomes a common context of births and people are more and more educated, these factors cannot be excluded from the study. We draw on Thomson and al.’s (2012) article, who find that in France, in the recent cohorts, completed fertility is less affected by union instability than in the past. They enlarge the prediction to the most recent cohorts using a microsimulation model. We extend this study by (1) adding marriages to the partnership history, (2) taking account of the level of education and time spent at school, (3) studying the mechanisms in other countries with different systems of value, the UK and later on Italy. In a first step, we describe the various changes in the countries under study: completed fertility, family trajectories, and the interrelationship between those. In a second step, we implement the microsimulation model that also includes levels of education. To do so, we use the coefficients from hazard regressions of transition to births (for up to 6 birth orders), to partnership (marriage or cohabitation as competing risks, on three orders), to separation and to repartnering. First descriptive results show that in the UK, women who separated by age 40 have continuously rather lower fertility than those in a stable union (birth cohorts 1940-1969). While repartnering enhanced fertility levels in the 1940s birth cohorts, it does not seem to be the case any more in the 1960s cohorts. Non-traditional family behaviours are still scarce in Italy in the cohorts described, but the microsimulation should unravel the most recent alterations.