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International Labour Migration Statistics (ILMS database)

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The ILOSTAT database on International Labour Migration Statistics (ILMS) is a set of indicators describing the number and profile of international migrant workers, their situation in the labour market and employment patterns, their main origin and destination countries and the magnitude of inward and outward migration flows. 

Concepts and definitions

According the ILO Guidelines concerning statistics on International Labour Migration endorsed by the 20th International Conference of Labour Statisticians in 2018, international migrants include all those residents of a given country who have ever changed their country of usual residence. For the purpose of practical measurement and in line with United Nations recommendations, international migrants may be measured as all persons who are usual residents of a country and who are citizens of another country (foreign population) or whose place of birth is located in another country (foreign-born population).  

Two criteria or variables allow for the identification of international migrants:

  • the citizenship, distinguishing between citizens and non-citizens (individuals not holding citizenship of the country of measurement)
  • the place of birth, distinguishing between native-born and foreign-born population (individuals born outside the country of measurement).

The ILMS database comprises international migrant stock and flow indicators.

Working-age population indicators include information on international migrant stocks, which represent the total number of international migrants of working-age present in the country of measurement at a particular point in time. This indicator measures the scale of working-age international immigration in the country. The stock of nationals abroad represents the total number of working-age citizens of the country of measurement, who have their usual residence in another country at a particular point in time. It measures the importance of working-age international emigration from the country.

The migration flow indicators measure the number of working-age international migrants entering and/or leaving the country of measurement during the reference period (a given year in the ILMS database) to establish their residence in the country (inflow) or abroad (outflow). Depending on the criterion used to define international migration, the inflow of international migrants includes either foreign-born individuals or non-citizens who moved to the country of measurement during the reference period to establish usual residence. For a given country, the outflow of nationals refers to the number of its citizens who left their country of citizenship to establish usual residence in another country during the reference period. As with stock indicators, only working-age international migrants are included in the flow indicators. 

Data sources

The main data sources for stock indicators are labour force surveys, followed by other household surveys and population censuses. Flow indicators usually come from administrative data sources. Administrative registration for residence or working permits from interior affairs or immigration services, foreign employment departments and other administrative services or border registration often allow for the measurement of new entries of migrants. Additionally, some household surveys may include information on migration flows. Stock and flow data may also come from various official estimates produced by countries based on multiple data sources.

In cases where ILO experts process the household survey microdata in order to produce the indicators published on ILOSTAT, international statistical standards are strictly applied to ensure comparability across countries. Thus, ILOSTAT data may differ from what is nationally reported. The magnitude of the differences depends on the extent to which a country is applying international statistical standards. 

Interpretation and uses

The working-age population indicators provide information on the share of migrants in the total population and inform on both their main origin countries and educational attainment. Employment indicators are disaggregated by migrant status, age, economic activity, occupation and status in employment. They illustrate the employment patterns of foreign-born/non-citizens in comparison with native-born/citizens and their contribution to the labour market. The difference in labour market outcomes reveals the economic inequalities between migrants and non-migrants and may reflect broader socio-economic barriers to the effective integration of migrants in destination countries.

Flow data provide information on the dynamic aspect of labour migration and on how the composition of the working-age population stock evolves over the reference period. The inflow indicators provide information on the importance and the profile of new annual entries of working-age migrants in the country. They also inform on the number of migrants moving to the destination country for work purposes, and the characteristics of their employment. The outflow indicators show the same information for nationals moving out of the country.


The two practical criteria used to define migrants both have advantages and disadvantages. The criterion of citizenship is relevant for policy, especially in terms of the right to work in destination countries. However, citizenship can change over time, people can hold multiple citizenships or not hold any (stateless persons), and being a foreigner does not necessarily imply that a person has actually migrated. Place of birth, on the other hand does not change, except in rare cases when country borders are redrawn, making people who never moved at risk of being wrongly classified as international migrants. Both criteria are widely available across countries, making the information relatively easy to collect. However, they may not describe migration trajectories as precisely as information on actual changes of country of residence undertaken by individuals or even the cross-tabulation of both criteria as recommended by the Global Migration Group.

Additionally, despite harmonization efforts over the years, countries are still using different concepts, definitions and measurement methods. For example, the concept of usual residence varies across countries, as some of them require a minimum duration of stay to classify an individual as a resident. This duration widely varies from three to twelve months, which may limit the comparability of stock and flow indicators across countries.

The data sources also have their limitations. Countries usually implement population censuses every ten years, therefore data are not frequently available and can be outdated, requiring countries to estimate their migrant population using different statistical methods. Household surveys, when not specifically designed for migration data collection, may produce data with limited reliability when only a small size of the migrant population is sampled. Administrative data usually only cover “registered” individuals. Derived stock and inflow indicators may thus exclude undocumented migrants and any immigrant who did not undertake formal administrative steps following his entry in the country. The register of nationals living abroad also cover only the emigrants who reported their absence to the relevant national or consular services. Therefore, statistics may provide an incomplete picture of international labour migration.


Note: Many publications are available only in English. If available in other languages, a new page will open displaying these options. 

ILO Global Estimates on International Migrant Workers – Results and Methodology

This report gives global and regional estimates, broken down by income group, gender and age. It also describes the data, sources and methodology used, as well as the corresponding limitations. The report seeks to contribute to the 2018 Global Compact for Safe, Orderly and Regular Migration and to achieving SDG targets 8.8 and 10.7.

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