The convergence of fertility between ethnic groups in the U.K.: the role of the immigrant and UK-born generations

Sylvie Dubuc, University of Oxford

In the UK, large differences in the level of fertility estimated by ethnic groups exist, although an overall convergence in fertility of the various ethnic groups has been measured (Dubuc, 2009). Despite this general trend, the pace of fertility convergence differs between ethnic groups, a divergent trend has been observed for the Chinese group, and lastly, the level and timing of childbearing between groups remain distinct in recent years (Dubuc and Haskey, 2010). Derived from the socialisation hypothesis, the assimilation hypothesis assumes that immigrants are influenced by fertility norms and behaviour in their country of origin. After migration, a process of fertility convergence with the destination country should occur from generation to generation towards the local norm. The socialization/assimilation theory implies that the level of fertility follows a function that depends on the ratio of UK-born versus foreign-born women within ethnic groups. Departure from this model would suggest persistence of structural (socio-economic) and/or normative (socio-cultural) inherited differences between groups. This hypothetical scenario was tested by estimating the fertility levels and age patterns of UK-born and foreign-born women of the various ethnic groups in the UK over the past 20 years. The method used here is thought to provide a valuable solution to minimize the increasingly documented risk of overestimation of fertility measured by period TFRs. The existing theoretical framework (e.g. selectivity and migration disruption effects, linear and segmented assimilation and minority status hypotheses) is used to discuss the findings. Overall results clearly suggest that the pace of convergence between ethnic groups is largely driven by the increasing proportion of the UK-born generations of women whose fertility approaches the UK average. However striking differences between ethnic groups deviate from classical assimilation theory expectations and suggest an important role of socio-economic factors in shaping fertility.