Fertility and migration
How to measure the fertility of immigrant women?
Erratum : on 22 February 2023, the completed fertility of immigrant women without diploma or with a diploma lower than baccalaureate was corrected following a revision of the nomenclature of diplomas of the TeO2 survey. Only figures 23 and 24 are affected, as well as the text related to figure 24.
The usual indicators measuring fertility from vital statistics and population estimates tend to overestimate the fertility of foreign-born women. Indeed, migration makes it difficult to statistically observe the entire fertile life of women born abroad. The new edition of the Trajectories and Origins survey (TeO2), more than 10 years after the first one, is an opportunity to analyse and illustrate the specificities of immigrant women in terms of fertility. In order to take these specificities into account, a new approach is proposed to measure the fertility of foreign-born women in a cyclical manner.
The first part of this paper presents the methodology associated with the indicators usually used to measure fertility. These are based on age-specific fertility rates, which relate the number of births in France from mothers of a given age to the population of women of that age residing in France. Yet for women born abroad, calculating these indicators in this way, without taking into account periods of lower fertility before migration, leads to an overestimation of their fertility.
The second part of this paper uses data from the second edition of the Trajectories and Origins survey to illustrate the findings of the first part and to analyse the fertility of immigrant women. The survey allows us to count all their children, not just those born in France or living with the respondent. It thus makes it possible to determine the complete final offspring of immigrant women. However, a one-off survey is not suitable for the cyclical measurement of fertility.
The third part therefore proposes a new method for calculating the Total Fertility Rate (TFR) for foreign-born women. This adjustment, which is based on modelling and a certain number of hypotheses, makes it possible to integrate periods of lower fertility, prior to migration, into the calculation of the TFR. This adjusted indicator, which is more representative, makes it possible to compare the fertility of women born abroad with that of women born in France.