The population dynamics of migration - some unveiling results of non-stable population growth

Thomas Salzmann, Rostock University

The process of population development between time t(0) and t(i) depends on changes in age specific rates of mortality, fertility, migration, and the age structure at time t(0). In aging societies migration is considered as one possible factor to control this process. Even if the net migration is zero the future population dynamics of in- and outflows of migrants do affect the population in an non-negligible way. But what share of the population development since a given time t(i) is solely ascribable to migration, and how is it possible to measure for a non-stable population? These questions will be tackled by applying a cohort-component model based on a partition of the aggregated-population into subpopulations A (natives), B (migrants), and C (descendents of the migrants) for some German federal states for the time period 1990 to 2005. The paper utilized data from the Federal Statistical Office.