There is no universally accepted definition of return migration. In the context of international migration, it refers to the movement of persons returning to their country of origin after having moved away from their place of habitual residence and crossed an international border. In the context of internal migration, the concept refers to the movement of persons returning to their place of habitual residence after having moved away from it (IOM, 2019a).
For statistical purposes, UN DESA defines returning migrants as “persons returning to their country of citizenship after having been international migrants (i.e., having established residence for the specified minimum duration) in another country and who are intending to stay in the country for at least one year” (UNSD, 1998: 94). The definition therefore embraces four dimensions: 1) country of origin; 2) place of residence abroad; 3) length of stay in the destination country; and 4) length of stay in the origin country after return. One of the challenges in measuring return migration is distinguishing return migrants from visitors, which is why length of stay in the destination and origin country are crucial bits of information.
UN DESA recommends that countries report data on stocks of returned migrants, or citizens of the country of enumeration who emigrated and subsequently came back to live in the country (GMG, 2017), which might be disaggregated by sex, age, destination country and migration status in the destination country prior to return. As the largest global provider of assisted voluntary return and reintegration, IOM publishes data on migrants supported by these programs disaggregated by sex, age, origin country, destination country and migration status in the destination country prior to return on their Assisted Voluntary Return and Reintegration (AVRR) website (IOM, 2019b).
Unfortunately, however, several countries implementing AVRR programs do not report data on those assisted and voluntary departures are usually not tracked. There is a large data gap on return migration due to a lack of definitions and indicators for measuring it. In 2016, the European Migration Network (EMN) developed a series of questions and indicators for inclusion in post-return monitoring activities that might help countries generate more data on return and reintegration, at least in the context of AVR and AVRR programs. The 15 field-tested indicators proposed by the EMN can be grouped into three different aspects of reintegration, namely, the economic, social and psychosocial dimensions (EMN, 2016).
Questions in household surveys or population censuses on the “year or period of arrival in country” might be directed to all persons who have ever lived abroad, regardless of their country of citizenship or country of birth, thereby generating data on return migrants (GMG, 2017). When adequate data are available, one can also match the origin country census against the censuses of the destination countries to estimate returns and also compare returning migrants to those who have remained behind in the host country. However, the drawback to this method is that it is not always possible to control for the date of arrival/length of residence in the destination/origin country. Data on migrants departing from the origin/destination country can be used to study return migration, but only if the next country/region of destination is recorded, otherwise one cannot separate return migration from secondary migration to another destination country. (OECD, 2008).