A conceptual framework for migrant fertility

Ben Wilson, London School of Economics and Political Science (LSE)
Wendy Sigle-Rushton, London School of Economics and Political Science (LSE)

Despite a long history of research on migrant fertility convergence (e.g. Hill 1913; Spengler 1931; Myers & Macisco 1975), it remains unclear how convergence should be defined, and how it should be investigated. This paper argues that empirical research on migrant fertility convergence (as well as assimilation and adaptation), is frequently undermined by a lack of explicit conceptual definitions. For example, recent research on European fertility states that a case of complete convergence has not been recorded (Sobotka 2008), but this observation seems at odds with the conclusions of earlier research (Coleman 1994). One reason for this is suggested by research on the US. Comparisons of different strands of research make it clear that conclusions about the convergence of Mexican and Hispanic fertility are dependent upon the way that convergence is defined, which in turn dictates the methods and measures used to compare the fertility of migrant generations (Bean et al. 2000, Frank & Heuveline 2005, Parrado & Morgan 2008). In order to provide a foundation for future research, this paper therefore undertakes a review of the concepts and methods that have been used to study immigrant fertility and that of subsequent migrant generations. The paper then proposes a conceptual framework that accommodates different definitions of fertility convergence, and allows research to be compared and contrasted, not least through an assessment of whether researchers have chosen the right data, methods and hypotheses in order to evaluate their research questions. Although just a starting point, this new conceptual framework shows the limits of current knowledge about migrant fertility, and helps future research gaps to be identified.