Replacement Migration

There is an almost four-decades old literature focused on the substitution effects of migration for the demographic processes of fertility and mortality. On the simplest level, the question came down to whether international migration could be used to alter purportedly unacceptable population size or composition due to fertility and mortality rates. Policy concerns have not only been about absolute population size as achieved or reasonably projected but also about composition, especially age composition because age structure can affect growth from future fertility, the size of the labor force and dependency ratios. Migration, like differential fertility in an ethnically, racially or religiously mixed population, can also affect the composition of social characteristics in a population that impact political or social events and opportunities.