Mind the gap: the role of involuntary factors in explaining the gap between desired and realized fertility in European countries - a microsimulation model

Alessandra Carioli, University of Southampton
Daniel Devolder, Centre d’Estudis Demogràfics (CED), UAB

Desired family size in low fertility countries is generally higher than the Total Fertility Rate, even after accounting for tempo changes that bias period fertility levels downward. In this work we employ Bongaarts (Bongaarts 2001) framework to discuss the role of the factors that explain the gap between desired and observed fertility and give a special attention to the role of involuntary factors. We consider two kinds of involuntary factors: biological factors and competing preferences. On one hand, biological factors (sterility, low fecundability, risk of miscarriage, etc.) may explain why a proportion of women who want children will remain childless or have less children than planned. On the other hand, social factors associated with family formation postponement and separation risks, may also explain why eventual fertility is lower than the desired fertility, due to the fact that very few women have births while living alone (e.g. after partnership disruption) or while enrolled in schooling. This article employs data from the Family and Fertility Survey for 11 European countries to compute all the estimates of observed and desired fertility by birth order, which allows us to consider childless women and mothers separately. We then apply a microsimulation model in order to estimate the role of these two kinds of involuntary factors in explaining the gap between observed and desired fertility across multiple scenarios considering changes in age at first birth and varying separation risks.