The cohort measurement of migration: the striking differences in population size to the effects of cumulative migration during the past decades for east and west German cohorts

Reiner H. Dinkel, University of Rostock

The existing data in Germany do allow a method to identify effects of cumulative net migration on the size of birth cohorts, if cohort life tables are available. From the number of life births and the probabilities to survive up to age x a potential number of cohort survivors can be calculated. This number would result, if either no migration at all or a strict equivalence of immigration and emigration would prevail between birth and age x. Post-war cohorts in the old West German states experienced an increase in the population size of up to 20 percent. Heavy losses are identifies for the newly-formed German states on the other side. The female cohort 1977 in Mecklenburg Pomerania for example already lost close to one half of its members (compared to the number without any migration effects). Consequences of these developments for population projections and other aspects are discussed.