research notes and comments: Distance weighted migration measures

This research note proposes new summary measures for migration that use geographic distance as a descriptive factor, establishing a linkage between migration fields and earlier measures of migration - net migration and migration efficiency. By factoring distance into migration efficiency and net migration, we create analogous and complementary measures defined as attraction efficiency and net attraction, respectively. These measures differentiate between proximate and distant migration flows and summarize the spatial extent of flows to or from a region that we discern in the study of migration fields. The analysis uses BEA level geography and migration data from the 1990 census to examine and illustrate these measures, and to compare the results with the traditional measures.