Migration

The relatively permanent movement of people across territorial boundaries is referred to as inmigration and out-migration, or immigration and emigration when the boundaries crossed are international. The place of in-migration or immigration is called the receiver population, and the place of out-migration or emigration is called the sender population. There are two basic types of migration studied by demographers:

1. Internal migration. This refers to a change of residence within national boundaries, such as between states, provinces, cities, or municipalities. An internal migrant is someone who moves to a different administrative territory.
2. International migration. This refers to change of residence over national boundaries. An international migrant is someone who moves to a different country. International migrants are further classified as legal immigrants, illegal immigrants, and refugees. Legal immigrants are those who moved with the legal permission of the receiver nation, illegal immigrants are those who moved without legal permission, and refugees are those crossed an international boundary to escape persecution.

Jay Weinstein and Vijayan Pillai (2001) denote a third classification: forced migration. Forced migration exists when a person is moved against their will (slaves), or when the move is initiated because of external factors (natural disaster or civil war). The distinction between internal and international migration is crucial because they happen for different reasons. Because structural barriers are more likely to impede the mobility of a potential international migrant than an internal migrant—international migration involves more administrative procedures, greater expense, and more difficulties associated with obtaining employment, accessing state services, learning a new language, and the like—the motivations behind international migration are usually stronger than those behind internal migration (Weeks 1999).