Net Migration Rate

The net migration rate expresses the net effect of migration on a population's size as a rate: net migration — in-migrants minus out-migrants over a period — divided by the population at risk, conventionally stated per 1000 people. It is the migration counterpart to the rate of natural increase and a standard component of population accounting. Because directional migration flows are often poorly recorded, net migration is frequently not counted directly but estimated as a residual from the demographic balancing equation or by comparing surviving cohorts across two censuses.