How has the statistical definition of international migration been revised?

The 1998 Recommendations defined an international migrant as “any person who changes his or her country of usual residence” and a person’s country of usual residence as “that in which the person lives, i.e., where they normally spend their daily period of rest”. The old recommendations suggest that a person who establishes residence in the new country for at least 12 months is referred to as a ‘long-term’ international migrant, while a person who establishes residence for at least 3 months but less than 12 months is referred to as a ‘short-term’ migrant (except for cases where the movement is for purposes of recreation, holiday, visits to friends and relatives, business, medical treatment or religious pilgrimage). The new recommendations emphasize, however that the term ‘short-term international migrant’ is a misnomer, as staying for a period of 3 to 12 months does not result in a change of residence (and may inflate the numbers of international migrants) (UN Expert Group on Migration Statistics, 2021).

In the latest revision to the United Nations Principles and Recommendations for Population and Housing Censuses (2017), countries were given two options in their census data collection when defining usual residents: one based on most of the last 12 months (6 months and one day) and the other based on at least 12 months (UNDESA, 2017). This has implications for the measurement of the resident international migrant population, which may correspond with one of two criteria: 1) foreigners who have lived (or intend to live) in the country continuously for most of the last 12 months (that is for at least 6 months and one day) not including temporary absences for holidays or work assignments or 2) foreigners who have lived (or intend to live) in the country for at least the last 12 months not including temporary absences for holidays or work assignments (UN Expert Group on Migration Statistics, 2021).

The terms “immigration” and “emigration” are implied depending on whether the reporting country or the country producing the statistics is a destination or origin country. From the perspective of the origin country, persons leaving the country to set up residence (for at least 12 months or most of 12 months) in another country are emigrants. From the perspective of the destination country, persons arriving to set up residence (for at least 12 months or most of 12 months) in the same country are immigrants (UNECE, 2011). It is important to note that persons who have moved to another country for a duration of less than six months and one day or less than 12 months, depending on the chosen criteria for residence, are not referred to as emigrants but as residents temporarily abroad (UN Expert Group on Migration Statistics, 2021).

The second major change to the 1998 Recommendations comes from the recognition that temporary (non-resident) population movements are as important to measure as international migration. The 2021 Conceptual Framework therefore identifies international migration as a subset of international mobility which is defined as all movements that cross international borders within a given year and includes both a) the resident population and international migrants and b) the non-resident population and movers. Movers therefore refer to foreigners who do not meet the minimum duration of stay for being considered a resident, which according to the revised framework could be less than 12 months or less than six months and one day. The Expert Group emphasizes that measuring international mobility requires statistics on both the resident population and the temporary population (UN Expert Group on Migration Statistics, 2021). Whereas the previous recommendations distinguished between a ‘short-term migrant’ and a ‘long-term’ migrant, the new convention is to refer to anyone who moved from one country to another for at least 3 months but for less than the 12 months criterion as a ‘mover’ (UNDESA, 2022).

International migrants are mostly identified as persons whose country of citizenship differs from their country of residence. The advantage of this measure is that it distinguishes access to a range of services and protections in a country and corresponds with the needs of policymakers. However, citizenship can change over time, a person can be a citizen of more than one country, a person can hold citizenship without having resided in the country, and a person can be stateless. International migrants might also be identified based on country of birth, if different from country of residence. The advantage of using country of birth is that it is consistent over time, however foreign-born persons might also include citizens residing in the country but born abroad and international borders may change over time. Therefore, the third major change to the 1998 Recommendations introduced by the 2021 revision is that countries are urged to collect data on both country of citizenship and country of birth, thereby producing statistics on four sub-groups, namely, foreign-born citizens, foreign-born foreigners (including stateless persons), native-born citizens and native-born foreigners (including stateless persons).