Until recently, efforts to construct bilateral migration datasets focused on the OECD countries as the destinations (OECD 2002, 2008), often including some disaggregation by other correlates such as age of entry, education, and gender. These data have informed the policy debate about various aspects of migration, for example the importance of various forms of brain drain (Beine et al. 2007, Bhargava and Docquier 2008) and the role of remittances (Ratha and Shaw 2008). We still lack a comprehensive overview of the evolution of migration patterns across geographic regions or income groups.
In recent research (Özden et al. 2011), we try to address this gap in our knowledge. We construct five 226-by-226 bilateral matrices of migration stocks by gender for each decade. We use the raw data from over 1,000 national censuses and population registers and then perform various numerical exercises to fill the gaps in the data. The main source for the raw data is The Global Migration Database which is the foremost depository of primary data on international migration and is maintained by the United Nations Population Division (UNPD). Because the data covering migrant destinations in these thousands of separate national censuses are not directly comparable – and therefore not suitable for analysis – a major effort has been devoted to harmonising the matrices and verifying the reliability of the resulting estimates.
Harmonising and completing the database
Since the global geopolitical landscape underwent many changes over the period covered by the censuses (1955-2004), the set of countries is standardised to those in existence in 2000. Some countries are aggregated to today’s nations (e.g. West and East Germany to Germany), and countries that no longer exist (e.g. Czechoslovakia) are allocated across successor countries on the basis of more recent migration figures.
It was also necessary to recode the data since definitions vary and destination countries’ censuses commonly aggregate the migration data into geographic regions (e.g. West Africa, South Asia, or Melanesia). The aggregate migrant numbers were then distributed amongst the origin countries that compose these regions using propensity measures. Further, miscellaneous categories (e.g. refugees, born at sea) were omitted such that the resulting data most appropriately refer to economic migrants.
Additional steps included reconciling census dates, varying definitions of migration, and calculating missing gender splits. Finally interpolation methods were used to construct missing census data. When the data were very poor (typically for small poor countries), it was necessary to rely on consistent totals from the UN “Trends in World Migration Stock” (2006) which were then subsequently disaggregated. (The technical issues and other aspects of this exercise are discussed in detail in Özden et al. 2011.)
Once the data have been prepared, a number of key trends in migration over the period 1960-2000 emerge.
Between 1960 and 2000, the total global migrant stock increased from 92 to 165 million. Initially, one fifth of the world’s migrant population was born in Europe, while around one third is attributable to both the partition of India and intra-Soviet Union migration respectively. Two thirds of the growth, up until 2000, was due to migrant flows to Western Europe and the US. Despite the sustained increase in the global migrant stock over the period, the migrant stock declined between 1960 and 1990 as a proportion of the world population, from 3.05% to 2.63%; after which it again rose to 2.71% in 2000.
Migration between the North and the South
The greatest growth in the number of migrants is largely driven by people migrating from the South to the North1, which increased from 14 million to 60 million over the period. The number of migrants from the North remained fairly stable however (Figure 1).
Figure 1. Stock of migrants by origin and destination
Figure 2. Migration shares
South-South migration declined as a proportion of world migration – from 61% in 1960, to 48% in 2000. However, when factoring in the migrant-creating effects of the partition of India and the breakup of the Soviet Union, South-South migration actually remained fairly stable over time, around a quarter of the total (Figure 2). As a share of the total, only South-North migration increased between 1960 and 2000, reflecting increasingly liberal immigration policies in the North. Over the period, the proportion of world migration attributable to South-North migration rose from 16% to 37%. This surpassed North-North migration between 1970 and 1980, both in terms of numbers and as a proportion of the total migrant stock.
Between 1960 and 2000, the migrant stocks in the US and Western Europe grew by 24.3 million and 22 million respectively, constituting around 42% of the world total in 2000. However, there exist notable differences in the migrant compositions of these two regions. Whereas the US’ immigrant profile has changed dramatically in terms of origin countries, Europe’s has remained far more stable, in part reflecting its continuing ties with ex-colonies.
The US is a particularly important recipient of migrants from all regions of the world. In 2000, the US was the most important destination for the migrants from sixty countries across the globe, including Germany, Vietnam, Cuba and Korea. Moreover, 13 of the largest 50 migration corridors in the world and 6 of the 10 largest South-North corridors in 2000 were to the US. The two most significant migration corridors to the US, from Mexico and the Philippines, totalled 10.8 million migrants, equivalent to 31% of the US migrant stock or nearly 7% of the world total.
Western Europe remains a key destination for migrants from around the globe. In 2000, two fifths of all Western European migrants lived elsewhere in Western Europe, driven largely by the economic and political integration of the European Union. Despite these increased numbers, intra-Western European migrants are increasingly becoming a minority as a proportion of the total migrant stock, especially since 1970, predominantly because of migration from the Southern countries. For example, the Turks and Poles in Germany constitute the two largest diasporas in Western Europe and the second and third largest South-North migration corridors globally. Elsewhere in Europe, the most significant migrant corridors from the South are from Algeria to France, South Asia to Britain, from the former Yugoslavia to Germany and from other countries in North Africa to France.
Migration to the South
Notwithstanding the partition of India and the disintegration of the former Soviet Union, migration to the oil-rich Persian Gulf States is arguably the most significant development in migration to the South. In 2000, 15% of all migration to the South (including both partition and intra-Soviet flows) was to the high-income Persian Gulf region, rising from under 3% in 1960. These movements are predominantly from South and South East Asia (45% of total migration to this region in 2000) and the low-income Middle East and North Africa (33% of the total in 2000) to the Gulf and from the countries of the former Soviet Union to Israel.
Migration from the North to the South, although declining over time, is not insignificant (see Figure 2). Today the most significant North-South movements are (i) from Western Europe to South America and the other countries of Europe and (ii) from the US to Central America (mostly Mexico) and the Caribbean.
The feminisation of migration stocks
In 1960, most regional immigrant stocks comprised proportionally more males. However, between 1960 and 2000 the gender composition of immigrant stocks changed fairly significantly. With the exception of South Asia, the numbers of women in each region rose in absolute terms. In terms of emigrant stocks, in absolute terms, all regions of the world sent greater numbers of women abroad in 2000. The largest proportional increase in the numbers was from Latin America and the Caribbean followed by the high-income Middle East and North Africa region. In 2000, the countries with the highest proportion of women in their emigration stocks were Ukraine (61%), Singapore (60%), and the Philippines (60%).
Beine M, F Docquier, and H Rapoport (2007), “Measuring International Skilled Migration: A New Database Controlling for Age of Entry”, The World Bank Economic Review, 21(2):249-254.
Bhargava, A and F Docquier (2008), “HIV Pandemic, Medical Brain Drain, and Economic Development in Sub-Saharan Africa”, The World Bank Economic Review, 22(2):345-366.
Organisation for Economic Co-operation and Development (2002), “Trends in International Migration: SOPEMI 2002 Edition”, Paris.
Organisation for Economic Co-operation and Development (2008), “A Profile of Immigrant Populations in the 21st Century: Data from OECD Countries”, Paris.
Özden, Caglar, Christopher Parsons, Maurice Schiff, and Terrie Walmsley (2011), “Where on Earth is Everybody? The Evolution of Global Bilateral Migration 1960-2000”, The World Bank Economic Review, forthcoming
Ratha, D and W.Shaw (2007), “South-South Migration and Remittances”, World Bank Working PaperNo. 102.
United Nations (2006), “Trends in Total Migrant Stock 1960-2000, 2005 revision”, Department of Economic and Social Affairs, POP/DB/MIG/Rev.2005/Doc, New York.
1 By the North, we mean Australia, Canada, EFTA, EU-15, Japan, New Zealand and the US.