On Distance and the Spatial Dimension in the Definition of Internal Migration

Migration is commonly defined by a temporal and a spatial dimension. It is generally agreed that these dimensions are problematic and could seriously distort understanding of migration, but data constraints have effectively obstructed further insights. This article focuses on the spatial dimension where migration is typically defined as movement across administrative borders. Borders usually serve as proxies for migration distance but the validity of such proxies is largely unknown, posing a considerable challenge to migration research. Using data for all internal migrants in Sweden, the only known country where migration distances are available in sufficient detail, we present the first accurate description of actual migration distances and investigate the relationship between actual migration distances and migration-defining boundaries. More specifically, we examine how the volumes of migration and the characteristics of migrants change when migration distances vary and when different types of migration-defining boundaries are employed. The findings show that notable shares of short-distance migrants are included almost regardless of which migration-defining boundary is employed, but migrant differentials are less affected than might be expected.