The Age of Mass Migration: What We Can and Can’t Explain

International migration has been a fact of life throughout the ages. But it is mass migrations that have changed the course of history and that hold a special fascination for social scientists and historians. None more so than the migration from Europe to the land-abundant, labour-scarce regions of the New World during the nineteenth century. In the century after 1820 some 55 million Europeans sought a new life in another continent and this experience has spawned a large literature. This rich literature spans a wide range of different approaches to the fundamental questions of who migrated, when and, above all, why and with what effect. Studies vary in scope, period, time and place, but they have increasingly become focused on specific streams of migrants, the communities they left behind and those they entered. These studies have greatly enriched our understanding of the characteristics of migrants and their specific circumstances.1 But the economic forces underlying mass migration have often taken a back seat to social, cultural and even political aspects. Research at the micro level on the particular, and sometimes the peculiar, group or community has been purchased at the cost of the economic and demographic fundamentals that more anonymously, but just as surely, drove the migrant flow.