International migration has been a central element in enriching many cultures and civilisations throughout human history, supporting the process of global economic growth and contributing to the evolution of states and societies. In the contemporary world it is a key issue in global integration and international relations due to its rapidly increasing economic, social and cultural impact in both the origin and destination countries.

Migration has considerable implications for demographic dynamics, indeed as the natural increase in population (births minus deaths) has slowed in many developed countries over the last decade, net migration is becoming an important source of population growth.

ESDS International hosts a number of datasets containing information about international migration. This guide will provide advice on finding both macro and micro data sources on migration.

The ESDS International catalogue can be searched for data on Migration using subject terms such as:

• "international migration"
• inflows or outflows

Use the ESDS International focused search found at www.esds.ac.uk/international/access/datasearch.asp to search across macro and micro international data. To access macro data at ESDS International you must be from a UK FE/HE institution.

Alternatively, the dataset descriptions of the international macro datasets www.esds.ac.uk/international/access/dataset_overview.asp provide a brief overview of the subject, geographic and temporal coverage of each of the datasets. More comprehensive detail is provided in dataset specific user guides at www.esds.ac.uk/international/support/dataset_guides.asp

The quality and comparability of international data on migration has not kept pace with the increasing attention from policy makers and the growing globalisation of economic activity. Data that are generally available on international migration flows do not provide a clear idea of the relative scale of movements across countries. In 1998 the UN revised its recommendations on international migration statistics but progress in improving the comparability of migration flow statistics since then has been slow.

Data on net migration tends to be more comparable than flow data as the differences arising from different definitions of short-term stays, which tend to vary most between countries, are minimised. Stock data is also generally more comparable than flows, as unauthorised immigrants are rarely reported in immigration statistics but may appear in surveys or censuses of the population. Due to the processes involved in treating asylum applications, data on asylum seekers have a high comparability.

It is estimated that remittances transferred by informal methods can account for almost half the total in some countries. As these informal transfers are not reported, cross country comparability for remittances is problematic.

The following macro datasets contain migration data:

• The OECD International Migration Statistics contain data on foreign and immigrant populations, foreign workers, migration flows and naturalisations for OECD and other countries from 1980 onwards.
• Eurostat New Cronos contains a data theme on ‘Population and Social Conditions’ which includes data on International Migration and Asylum.
• The International Labour Organisation Key Indicators of the Labour Market collects and compiles international labour migration statistics.
• The UN Common Database contains data on net migration, migrant stock and migration projections to 2050.
• The World Bank’s Global Development Finance Database contains information on Workers' remittance

The international micro datasets at ESDS International:

A number of the Eurobarometers, the ISSP National Identity modules, the European Social Survey, and the World and European Values Surveys ask respondents about their attitudes towards immigrants. The Eurobarometers also ask about the respondent's nationality, ISSP includes respondent's ethnicity, nationality and family-origin and the Values surveys include ethnic group.

The International Passenger Survey aims to collect data on both credits and debits for the travel account of the Balance of Payments, provide detailed visit information on overseas visitors to the United Kingdom for tourism policy, and collect data on international migration.

Access ESDS International macro data at - www.esds.ac.uk/International/access/dataset_overview.asp and micro data at www.esds.ac.uk/international/access/micro.asp.

Use the CommonGIS interface to visualise CIA World Factbook migration data - www.esds.ac.uk/international/access/commonGIS.asp.

Net Migration rate shown here is the difference between the number of persons entering and leaving a country during the year per 1,000 persons (based on midyear population). An excess of persons entering the country is referred to as net immigration ; an excess of persons leaving the country as net emigration. The net migration rate indicates the contribution of migration to the overall level of population change.

The International Organization for Migration (www.iom.int/) is dedicated to promoting humane and orderly migration for the benefit of all. IOM acts with its partners to: uphold the human dignity and well-being of migrants; encourage social and economic development through migration; assist in meeting the growing operational challenges of migration management; and advance understanding of migration issues.

The United Nations Development Programme’s (www.undp.org/) aim is to maximize the developmental benefits of migration for poor countries, and mitigate any negative consequences. UNDP country offices provide capacity development support to governments that wish to develop pro-poor, pro-development and human rights-based migration strategies, as part of their broader MDG-based national development strategies.

The World Bank's (www.worldbank.org/) engagement on international migration focuses on the development impact of migration and remittances for developing countries. The focus to date has been largely on generating reliable data and deepening existing knowledge on the potential benefits and costs of migration at both the household and aggregate level which has lead to improved availability and quality of data on priority issues.

The United Nations High Commissioner for Refugees (www.unhcr.org/) collects and compiles data on asylum seekers and refugees more specifically on asylum applications, refugee status determination, recognition rates, refugee populations and movements, demographic characteristics (age and sex) as well as major refugee locations.

The United Nations Population Division (www.un.org/esa/population/unpop.htm) undertakes regular studies on population levels and trends, population policies and population and development using the data provided by the United Nations Statistics Division.