1 Migration: Concepts and Patterns
Learn how migration is defined, classified, patterned across places, and measured through arrivals and departures.
Defining
is a move away from a person’s usual residence to establish residence elsewhere, either within the same country or across an international border. It differs from short-term travel, such as a holiday, because it involves changing where a person lives.
The time or residence threshold used to count a move is not always the same. It depends on the data source; some statistical measures, for example, compare a person’s residence at two specified dates.
The terms and describe a movement from different perspectives. is movement out of a place, while is movement into a place. A person moving from Mexico to the United States is an emigrant from Mexico and an immigrant to the United States, so the same movement can be an outflow for one place and an inflow for another.
Classifying types of
can be classified by boundary crossed, geographic scale, duration or recurrence, and circumstance. These classifications can overlap: a person may migrate internationally for temporary seasonal work, or be displaced within their own country.
By boundary crossed: Internal (domestic) takes place within a country, whereas crosses a national border. A move between states is in the United States; a move from the United States to Canada is international.
By distance or geographic scale: A move may be local, regional, or long-distance. A local move may cross a neighborhood or county boundary; a regional move may connect areas within a larger region; and a long-distance move may cross an entire country or an international border. Scale describes the reach of movement, not its cause.
By duration or recurrence: lasts for a limited period. involves a lasting change of residence. recurs at particular times of year, often in response to employment or climate conditions. involves repeated movement between places, and is a move back to a previous home or place of residence. Statistical definitions of temporary and long-term use specified time thresholds, which may differ from everyday usage.
By circumstance: is undertaken by choice, although circumstances may constrain choices. occurs when people must leave or are compelled to leave. A has crossed an international border and meets a specific protection definition. An has been forced to leave home but has not crossed an internationally recognized border.
Spatial patterns and flows
A is movement from an origin to a destination over a period of time. Geographers describe flows by their direction, distance, volume, and the places they connect.
Common spatial patterns include:
Rural-to-urban: Movement from rural areas to cities, often associated with employment, education, or access to services.
Urban-to-urban: Movement between cities, such as relocating from a smaller city to a larger metropolitan area.
Rural-to-rural and urban-to-rural: Movement between rural areas, or from a city to a rural area.
: Movement through a sequence of places, such as from a village to a small town and later to a major city.
: Movement in which family or community connections help people follow earlier migrants to a destination.
Return and circular flows: Movement back to an earlier place, or repeated movement between places.
These patterns are not fixed. A person can move through more than one stage, and the same destination may attract some migrants while others leave it.
Measuring
counts arrivals and departures separately. is the difference between the number of people arriving and the number leaving a place during a specified period.
If 12,000 people move into a region and 9,000 move out, its is . This balance summarizes the difference between arrivals and departures, but does not show the full size or direction of all flows.
Describing a
To describe a clearly, identify its origin and destination, the scale and duration of movement, and the classification being used. may be internal or international, local or long-distance, temporary or long-term, voluntary or forced, and may follow seasonal, circular, return, or other spatial patterns.