DIFFERENTIATING BETWEEN SUBSYSTEMS AND TYPOLOGIES IN THE ANALYSIS OF MIGRATION REGIONS - A UNITED-STATES EXAMPLE

Studies of migration regions are characterized by two separate concept ual approaches. The first views migration regions as clusters of highl y interconnected spatial units (subsystems) while the other defines th em as groups of spatial units with a similar geographic structure of f lows (typologies). This paper highlights the theoretical and methodolo gical distinctions between migration subsystems and typologies. An emp irical analysis using U.S. migration data for 1940, 1960, and 1980 sho ws that although migration subsystems and typologies have both changed over time, each reveals a different dynamic of regional change and ha s different morphological characteristics.