What is Migration?

Migration is the movement of persons away from their place of usual residence, either across an international border or within a State, to a new residence. Migration has emerged in the last few years as a critical political and policy challenge in matters such as integration, dis-placement, safe migration and border management. Module 1 introduces students to the migration cycle, population change and human mobility.

The migration cycle

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The Migration Cycle

Source: Figure elaborated in the World Migration Report 2022

Key terms

  • Migration
  • Migration Cycle
  • International Migration
  • Internal Migration

Key resources on the topic


Internal and international ‘migration’

For demographic purposes, migration can be classified into two broad types: international and internal migration. In a general sense, ‘migration’ is the process of moving from one place to another. To migrate is to move, whether from a rural area to a city, from one district or province in a given country to another in that same country, or from one country to a new country. It involves action. International migration occurs when people cross state boundaries and stay in the host state for some minimum length of time. When people move within a country it is called internal migration. Migration from rural areas to urban locations within a country is called ‘urbanization’.

Difficulty of obtaining migration flow data

Capturing data on migration flows is extremely challenging for several rea-sons. For instance, while international migration flows are generally accepted as covering inflows (flows of migrants entering into a particular boundary) and outflows (flows of migrants leaving a particular boundary) into and from countries, there has been a greater focus on recording inflows.

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Inflows of foreign nationals into OECD countries

Source: OECD, n.d.a, World Migration Report 2022, Chapter 2

For example, while countries such as Australia and the United States count cross-border movements, many others only count entries and not departures. Additionally, migration flow data in some countries are derived from administrative events related to immigration status (for example, issuance/renewal/withdrawal of a residence permit) and are thus used as a proxy for migration flows. Furthermore, migratory movements are often hard to separate from non-migratory travel, such as tourism or business. Tracking migratory movements also requires considerable resources, infrastructure and IT/knowledge systems. This poses particular challenges for developing countries, where the ability to collect, administer, analyse and report data on mobility, migration and other areas is often limited. Finally, many countries’ physical geographies pose tremendous challenges for collecting data on migration flows.

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Key migration data at a glance

Reflection questions

  1. Explain the difference between ‘international migration’ and ‘internal migration.’

  2. During the “migration cycle”, do all migrants pass through a border point on entry? Please explain your answer and provide examples.

  3. Briefly explain two reasons why obtaining migration flow data can be difficult.

  4. Examine the migration data figure and describe the changes in patterns in your own words.