The research leading to these results is part of the DEMIG project and has received funding from the European Research Council under the European Community's Seventh Framework Programme (FP7/2007-2013)/ERC Grant Agreement 240940. The authors would like to thank Edo Mahendra, Maria Villares-Varela, and Simona Vezzoli and three anonymous referees for the valuable comments they have on a previous draft of this article.
The copyright line in this article was changed on 14 January 2016 after online publication.
Although it is commonly believed that the volume, diversity, geographical scope, and overall complexity of international migration have increased as part of globalization processes, this idea has remained largely untested. This article analyzes shifts in global migration patterns between 1960 and 2000 using indices that simultaneously capture changes in the spread, distance, and intensity of migration. While the results challenge the idea that there has been a global increase in volume, diversity, and geographical scope of migration, main migratory shifts have been directional. Migration has globalized from a destination country perspective but hardly from an origin country perspective, with migrants from an increasingly diverse array of non-European-origin countries concentrating in a shrinking pool of prime destination countries. The global migration map has thus become more skewed. Rather than refuting the globalization of migration hypothesis, this seems to reflect the asymmetric nature of globalization processes in general.
It is commonly assumed that international migration has accelerated over the past fifty years, that migrants travel over increasingly long distances, and that migration has become much more diverse in terms of origins and destinations of migrants (Arango, 2000: 291). In this context, Vertovec (2007) coined the term “super-diversity” to indicate the unprecedented degree of immigrant diversity in Britain and other immigrant-receiving societies. This is based on the idea that an increasing number of “new, small and scattered, multiple-origin, transnationally connected, socio-economically differentiated and legally stratified immigrants” (Vertovec, 2007: 1024) have recently arrived and settled in destination societies. It has also been argued that with the increasing integration of societies in international migration systems (cf. Skeldon, 1997), more and more countries are experiencing significant volumes of immigration and emigration.
All these trends combined suggest that global migration patterns have become more complex. This is opposed to the assumed lower diversity and neater structuring of past migrations, in which more clear-cut division between immigration and emigration countries would have existed. This is also linked to the idea that, in the past, migration often concentrated in a few bilateral corridors, frequently following colonial and other historical links. For instance, the vast majority of transcontinental migrants from Francophone Africa moved to France, while migrants from Anglophone Africa tended to move to the UK (Bakewell and de Haas, 2007). In recent decades, these patterns seem to have become more diverse with a “fanning out” of migration to new destinations in Southern Europe, the Gulf and Asia.
The assumed increases in the volume, diversity, geographical scope, and overall complexity of international migration are commonly linked to advances in transport and communication technology and more generally to globalization processes. Globalization can perhaps best be defined as the “widening, deepening and speeding up of worldwide interconnectedness in all aspects of contemporary social life” (Held et al., 1999: 2).
Globalization should be simultaneously seen as a technological and political process. Technological revolutions have radically reduced the costs of (air) travel and communication over increasingly long distances (Castells, 1996). The common assumption that technological change has facilitated migration along increasingly diverse geographical pathways is threefold. First, technological change has lowered resource constraints on mobility – the threshold levels of wealth required to move – by bringing down costs of travel and communication. Second, it has strengthened migrant networks and transnational ties by making it easier to stay in touch with family and friends, to remit money, and to travel back and forth between destination and origin countries (cf. Faist, 2000; Vertovec, 2001, 2004). Third, increased literacy and education alongside improved access to “global” information through (satellite) television, mobile phones, and Internet seem to have increased people's aspirations and awareness of opportunities in previously unknown countries. Combined, these processes seem to have increased people's capabilities and aspirations to migrate (de Haas, 2009).
It is, however, important to emphasize that modern-day globalization is not only driven by technological progress, but also by political and ideological change. Since the 1980s in particular, there has been a global political trend toward laissez-faire economic policies, which went along with the gradual, albeit asymmetrical, lifting of international barriers for trade and capital flows. This process gained momentum in the 1980s with the Reagan and Thatcher governments in U.S. and the UK, respectively, pushing the agenda for domestic and international economic deregulation. This trend was further accelerated after the fall of the Berlin Wall in 1989 heralding an age of “market triumphalism” (cf. Jones, 1998) and the dominance of the Washington Consensus on the importance of market liberalization, privatization, and deregulation (Gore, 2000; Stiglitz, 2002: 67). Thus, while globalization has been facilitated by technological progress, the process is also driven by ideological shifts and political change toward an assumed “universalization of Western liberal democracy” (Fukuyama, 1992) across the globe.
A key dimension of globalization is a rapid increase in cross-border flows of all sorts, starting with finance and trade, but also ideas, ideologies, and knowledge about democratic and economic governance, cultural and media products, and people (Castles and Miller, 2009). These flows seem to reinforce each other. For instance, increasing trade, investment, communication, and international aid links appear to reinforce migration links and/or vice versa, at least in the short run (Schiff, 1994; Czaika and Mayer, 2011). This seems to confirm the key proposition of migration systems theory that one form of exchange, such as trade, between countries or places is likely to engender other forms of exchange, such as people, in both directions (Mabogunje, 1970; Kritz, Lim, and Zlotnik, 1992; Massey et al., 1998).
The core idea is that growing social, economic, and cultural interconnectedness epitomized by the concept of “globalization” has facilitated migration in ever greater numbers between an increasingly diverse and geographically distant array of destination and origin countries. Other factors that seem to explain surging migration are increasing international and domestic inequalities, the persistent demand for high- and low-skilled migrant labor in the segmented labor markets of wealthy societies, and the lack of opportunities, population growth, oppression, and violent conflict in developing countries. Several of these factors, such as growing labor market segmentation and domestic inequality, are affected by the same political trends toward market liberalization and economic deregulation that have also boosted the economic globalization (cf. Wade, 2004).
In this vein, Salt (1992) argued that the contemporary geography of labor migration reflects the globalization of the world economy and labor markets, in which an increasing number of countries have become participants in global migration systems. He therefore spoke of “the globalisation of international labour migration” (Salt, 1992: 1080), in which “all countries now engage in migration systems growing in size and complexity and producing an increasing diversity of flows.” Further, Castles and Miller (2009) argued that there has been a “globalization of migration,” which is “the tendency for more and more countries to be crucially affected by migratory movements at the same time” (Castles and Miller, 2009: 10). This would correspond with a diversification of immigrant populations, in which “most countries of immigration have entrants from a broad spectrum of economic, social and cultural backgrounds” (Castles and Miller, 2009: 10).
The widely assumed acceleration of global migration would have occurred along with a diversification of migration in terms of composition of immigrant populations not only in terms of countries of origin, but also in terms of migration categories, in which labor, student, family, and asylum migration as well as temporary and permanent migration would increasingly coexist (Castles and Miller, 2009: 11–12). Global migration is also believed to have feminized, with more and more women independently migrating instead of “dependent” family migrants (Zlotnik, 1998; Jureidini and Moukarbel, 2004; Ramírez, García Domínguez, and Míguez Morais, 2005).
While there is broad consensus that the volume, diversity, geographical scope, and overall complexity of migration have increased under the influence of broader globalization processes, these assumptions have not been subjected to systematic empirical assessment. This is unfortunate, as there is reason to challenge these assumptions. Zlotnik (1999) already questioned the consensus view that international migration is accelerating by showing that the percentage of people living outside their country of origin is “remarkably small and has been relatively stable for a long period” (Zlotnik, 1999: 42). Her analysis of data from the United Nations Population Division (UNPD) showed that between 1965 and 1990, this percentage has oscillated between 2.1 and 2.3 percent of the world population.
There is also cause to question the diversification hypothesis. While some European countries may host an increasingly diverse array of immigrants from increasingly distant countries, we cannot automatically extrapolate this Eurocentric observation to the global level. For instance, while South American countries used to attract large numbers of migrants from a remarkably diverse array of countries beyond Europe (including Japan, India, China, and Lebanon), this diversity seems to have decreased in recent decades, with a stronger focus on intra-regional migration.
We may also question the idea that the geographical scope of migration has increased. For instance, several European countries have seen large-scale immigration from (often very distant) ex-colonies between 1950 and 1990. However, in more recent years, there has been a surge in immigration from (less distant) Eastern European countries. While Australia and New Zealand used to almost exclusively attract migrants from (extremely distant) Europe, they now attract increasing numbers of migrants from (less distant) Asian countries. This also shows the importance of distinguishing between emigration and immigration patterns.
The latter observations also demonstrate the need to look beyond global averages. The focus on global migration rates is likely to conceal significant differences in the extent to which the volume, diversity, and geographical scope of migration have changed on a global level and across world regions. To understand how global migration patterns have changed, it is necessary to go beyond the usual focus on the volume of migration by analyzing underlying changes in the geographical scope, diversity, and directionality of migration. This is important for three reasons. First, globalization may not necessarily manifest itself in a change in the volume, but rather the underlying spatial patterns of migration. Second, it is unlikely that “globalization” has affected regions in a uniform way, making it crucial to analyze the regional trends that underlie global patterns. Third, it is unlikely that globalization has had a similar impact on immigration and emigration patterns.
There is a lack of studies that explore in detail how the global spatial patterning of migration has evolved over the past decades. The best available studies analyze migration trends between and within the global “South” and “North” and the major migration poles (e.g., Özden et al., 2011). Such studies have provided valuable insights into the major shifts in inter-continental migration. There, however, remains a need to go beyond crude and highly problematic distinctions between “South” and “North” (cf. Bakewell, 2009) to achieve a more nuanced understanding of how global migration patterns have changed in volume, diversity, direction, and geographical scope.
This article aims to fill these empirical and conceptual gaps by analyzing the evolution of global migration patterns between 1960 and 2000 through mapping changes in the direction, intensity, geographical spread, and distance of international migration. To simultaneously capture changes in the geographical spread, distance, and intensity of migration (and a more general “complexity” dimension) and distinguish between immigration and emigration patterns without relapsing in crude distinctions between emigration and immigration countries, this article elaborates country-level indices for emigration dispersion and immigration diversification. These two indices are amalgamated in country-level indices of migration globalization. The ensuing empirical analysis will serve to evaluate the following propositions:
Migration has become more intense in terms of the relative number of people moving;
Migrants have moved over increasingly long distances;
More and more countries have become connected to international migration systems and experience increasing volumes of immigration and emigration;
Partly because of (2) and (3), migration has become more diverse in terms of origin countries of immigrants and destination countries of emigrants; and
Migration has become less concentrated in particular bilateral (country-to-country) migration corridors.
Conceptually, all these propositions can be related to a more overall (functionalist) concept of a global diffusion of migration experiences and a concomitant level of equalization (“flattening”) of access to international migration. We can call this the globalization of migration. If this globalization of migration has occurred, this should have resulted in a general diversification in origins of immigrants and destinations of emigrants and a decreased spatial clustering of international migration along particular migration corridors. The capacity to perform the analyses required to assess these propositions has been drastically improved, thanks to the release of the Global Bilateral Migration Database (GBMD) by the World Bank.2 This database contains bilateral migration population data for 226 countries, major territories, and dependencies (Özden et al., 2011; World Bank 2011). As their primary source of information, the database used more than one thousand national censuses and population registers to estimate complete decennial global origin–destination migration matrices for each decade from 1960 to 2000. The database used the UN definition of a migrant, also used by most national statistical offices, that states “[…] a (long-term) migrant is a person who moves to a country other than that of his/her usual residence for a period of at least 12 months, so that the country of destination becomes his/her new country of residence” (United Nations 1998). Migrant's origin is mostly defined by their country of birth, only in a few cases by the country of citizenship. The fact that censuses generally cover the entire resident population at a single point in time implies that documented and many undocumented migrants are enumerated (Özden et al., 2011). However, due to the GBMD database's focus on migrant stocks, it mainly captures long-term international migrants and is likely to miss out much temporary and circular movement and various forms of non-migratory mobility. Although still far from perfect, this database has radically expanded and provides new opportunities in advancing our understanding on long-term migration processes on a global level. The comprehensiveness of the GBMD enables us to analyze the evolution of global migration patterns at a level of detail that was not possible before.
The aim of this analysis is not to study short- or medium-term fluctuations in migration flows such as those related to the recent global economic crisis, but rather a description of the general picture of how the overall structure of global migration has changed of the past half a century. This type of analysis has only become possible due to the recent progress made on collecting census-based migrant stock data with global coverage.
Conceptualizing the Globalization of Migration: Intensity, Spread, and Distance
Before we can turn to the empirical analysis, it is necessary to define the key concepts of intensity, diversity, and distance and the more general concept of the globalization of migration. Such concepts are often not defined, and this easily renders analyses vague. For instance, what do we mean by intensity of migration, and how do we measure it? Can we use absolute numbers, or is this deceiving and should we rather express this in relative numbers such as the shares of the total population?
What do we mean by diversification of migration? This is not obvious, as we can look at this dimension from various angles. First of all, do we mean diversification from an origin country (emigration patterns) or destination country (immigration patterns) perspective? Does this pertain to the spread of migrant origins (for destination countries) and migrant destinations (for origin countries) or to the idea that migrants come from and go to more diverse countries in terms of geographical distance and, hence, cultural and phenotypical differences? Or, does a diversification simultaneously encapsulate spread and distance? So, diversification is a potentially multidimensional concept and hence the need to clearly define and operationalize this key concept.
Distance is a similarly ambiguous concept. The default position is to use geographical distance as a yardstick, although some would argue that this is becoming a less relevant factor in a globalizing world and that distance should rather (or also) be expressed in terms of legal, phenotypical, cultural, or linguistic distance as these are the barriers that really matter. For instance, Britons migrating to New Zealand may go to the other side of the world, but they cross a smaller linguistic and cultural distance than if they would migrate to France. Although it is often stated that migration is becoming increasingly complex under the influence of globalization processes, such complexity is rarely defined or operationalized. And what does complexity actually mean? Complexity does not mean that migration is chaotic or devoid of regularities, but it rather means that the patterns are elaborate and multilayered. But elaborate in which ways?
To base the empirical analyses on an unequivocal conceptual basis, this article will define, decompose, and operationalize the central concepts intensity, diversity, and distance. Subsequently, these subcomponents will be aggregated into one composite measure of migration globalization, reflecting the extent to which international migration has undergone a spatio-temporal diffusion process.
With regard to intensity, it is important to clearly distinguish absolute and relative numbers. It is only possible to speak of a growing intensity or acceleration of migration if migrants constitute an increasing percentage of a population, reflecting an acceleration of migration rates. We also need to maintain a distinction between global migration intensity and country-level emigration and immigration intensity, because a stationary global migration rate may conceal important changes in country-level migration levels.
Second, the concept of diversification seems to simultaneously capture three subdimensions: migration intensity, migration spread, and migration distance. The migration diversification hypothesis is that all three dimensions have increased under conditions of globalization. In practice, this would imply that growing immigrant populations have also diversified by coming from an increasingly geographically distant and diverse array of origin countries. We call this immigration diversification. From an origin country perspective, the idea is that growing numbers of emigrants have dispersed to an increasingly diverse array and geographically distant array of destination countries. We call this emigration dispersion.
From this, we can define and conceptualize migration globalization as functionally related processes of emigration dispersion and immigration diversification. The idea is that if immigration diversification increases, we also expect emigration dispersion to increase and vice versa. This also provides the basis for a more concrete and verifiable operationalization of the common, but rather vague idea that migration patterns have increased in complexity. This seems to reflect the idea that migrants move along less uniform spatial pathways in a less socially and politically organized manner. Disorganized does not mean chaotic. It rather implies that migration patterns have evolved more spontaneously than in the past, where the impression is that governments were more actively involved in, for instance, the recruitment of labor and “guest workers” as well as assisted emigration.
Table 1 displays these three conceptual dimensions of migrant globalization from both an origin and a destination country perspective. Taken together, these three dimensions reflect what we can refer to as the “globalization of migration” as they match rather close the idea that globalization can be defined as the widening, deepening, and speeding up of worldwide interconnectedness (Held et al., 1999: 2). This can also theoretically be rooted in Zelinsky's (1971) and Skeldon's (1997) conceptualization of migration as a spatio-temporal diffusion process, which reflects the idea that more people will start moving in increasing numbers and over increasingly long distances as a result of demographic and concomitant economic and urban transitions embodied in the concept of “development.” So, as countries develop and become integrated in global economic, political, and social systems, we can also expect that their migratory interconnectedness increases.
Table 1. Theoretical Dimensions of Migration Globalisation
Emigration dispersion (origin country perspective)
Immigration diversification (destination country perspective)
Following this conceptualization, globalization of migration would not only imply that migration has accelerated, but also that migration has become more complex through an increasing geographical diversity and scope of migratory pathways. A final assumption is that globalization increases migratory interconnectivity in both directions. This can be rooted in migration systems theory (Mabogunje, 1970; Skeldon, 1997; Massey et al., 1998) and earlier observations by Ravenstein (1885) and Lee (1966), according to which flows of people (as well as flows of ideas, goods, and capital) in one direction are likely to generate migratory counterflows in the medium to longer term. This also helps us to overcome crude distinction between immigration and emigration countries.
So, if the globalization of migration hypothesis holds, one should expect growing emigration dispersion and immigration diversification, with more countries simultaneously experiencing accelerating immigration and emigration from and to an increasingly diverse and geographically distant array of origin and destination countries. The next section on [kursiv: Globalization of Migration since 1960] will assess the basic propositions that the intensity, diversity, and geographical scope of migration have increased. It will also assess major changes in directionality of migration. To further assess the globalization of migration, the section on [kursiv: Migration Globalization at the Country Level] will amalgamate, elaborate, and analyze indices for emigration dispersion, immigration diversification, and a composite Migration Globalization Index.
The Globalization of Migration since 1960
Global Migration Patterns: Intensity, Spread, and Distance
Drawing on the Global Bilateral Migration Database (GBMD), this section assesses the hypotheses that international migration has become more (1) intense; (2) spread; and (3) geographically distant on a global, regional, and national level and that there has been a particular increase in migration from developing to developed countries. Table 2 displays the number of net immigration versus net emigration countries. Over the last decades, the number of countries and territories with net immigration has shrunk from 102 to 78, while the number of net emigration countries has increased from 124 to 148. Between 1960 and 2010, 46 countries shifted from being a net emigration to a net immigration country, while 70 countries made a reverse transition. This can be partly explained using migration transition theory, which predicts an inverted U or J pattern in terms of the impact of development on migration, with initially increasing emigration as countries develop (de Haas, 2010; Skeldon, 2012).
Table 2. Number of Net Immigration and Emigration Countries and Territories (N = 226)
Source: Authors' calculations. The total number of countries and territories (N = 226) has been kept constant over time although many countries (dis-)integrated during this time period (Germany, Soviet Union, Yugoslavia, etc.). Based on census data, the GBMD recalculates for earlier periods respective stocks of migrants for countries which were formerly unified or independent.
Net emigration countries
Net immigration countries
Transition from emigration to immigration country
Transition from immigration to emigration country
The underlying idea is that improvement in infrastructure, income, education, and information increases people's capabilities and aspirations to migrate. While the poorest countries often have relatively low emigration and can even be net immigration countries (particularly when they were areas of European settlement or the destination of refugee populations or international humanitarian workers), middle-income countries typically experience high net emigration. Only after sustained period of growth and development, emigration tends to decrease, while immigration increases, explaining how after this emigration–immigration transition countries transform into net immigration countries in the “last stage” of migration transitions.
First, West European countries have massively entered the last stage of the migration transition, with countries transforming from high-emigration to high-immigration countries. This is linked to a broader, global reversal in migration patterns. While for centuries, Europeans have been moving outward through conquering, colonizing, occupying, fleeing, and settling in lands elsewhere on the globe, these patterns reversed in the second half of the twentieth century. Under the influence of decolonization, demographic change, rapid economic growth, and the creation of the European Union (EU) as a free trade and migration zone, the expanding Union has emerged as a global migration magnet.
The decreased relative importance of Europe as a source of migrants is linked to fundamental shifts in global migration patterns. Declining European emigration coincided with a second shift in migration patterns, that is, increasing immigration from South and Southeast Asia and (for North America) Latin America to traditional countries of settlement, principally the U.S., Canada, Australia, and New Zealand. Third, several Latin American countries have experienced a drastic reduction in immigration and rapidly increasing emigration, while some countries, including Panama, Peru, Brazil, and Honduras, have witnessed reverse migration transitions, from net immigration to net emigration countries. This reflects the declining position of Latin America in the global wealth ranking and declining immigration from Europe, the traditional source of immigrants to the Americas.
A fourth shift has been the rise of new global migration magnets outside of North America, Australia, New Zealand, and Europe, principally in the Persian Gulf regions (particularly since the 1970s), the “Asian Tiger” economies (principally Singapore and Korea) as well as Japan. A fifth shift was that many developing countries have entered a migration transition (see above), coinciding with emigration hikes. Many current high-emigration countries, including Yemen, the Philippines, Turkey, Morocco, Egypt, and India, were weakly integrated into international migration systems, and several used to be immigration countries in 1960.3 Since then, certain levels of development, rising education, infrastructure improvement, and increased international interconnectivity seem to have boosted emigration from those countries. Although most migration was initially mostly regional, migrants have increasingly moved further afield, toward North America, Europe, Australia, and New Zealand, as well as Japan, South Korea, and the Gulf Region. In some countries, such as Afghanistan, Angola, Somalia, Sudan, and former Yugoslavia, emigration hikes were primarily related to refugee movements. After the fall of the Berlin Wall in 1989, several Central and Eastern European countries also experienced high increases in emigration. Table 3 compares estimates of net migrant populations in the 15 major emigration and immigration countries for 1960 and 2000 and highlights these shifts in global migration patterns. The U.S. has reinforced its position as the world prime destination. In 2000, it was home to approximately 35 million migrants, which was equal to about 21 percent of the estimated 167 million migrants in the world. In 1960, the U.S. was home to only 12 percent of all international migrants. While in 1960, Argentina and Brazil were home to the second and ninth largest net immigration stock in the world, they have moved significantly down the list since then. By contrast, Gulf economies have become prime destination, while European countries have consolidated their position.
Table 3. Top 15 Net Immigration and Net Emigration Countries, 1960 and 2000
Net stock [in million]
Net rate [in%]
Net stock [in million]
Net rate [in%]
Source: Authors' calculations.
While in 1960, Italy, the UK, Spain, and Greece were prime countries of emigration, in 2000, their place has been taken by countries such as Mexico, Bangladesh, India, the Philippines, Egypt, Turkey, Vietnam, Indonesia, and Morocco. Although China is still an important origin or sending country, the numbers are relatively low compared with its total population. Further, the absolute number has hardly changed over the past four decades, suggesting that emigration rates are actually declining.
What these figures also suggest is that there has been an increasing “skewness” in the distribution of migration destinations compared with migration origins, which implies an increasing concentration of the global migrant population in a shrinking number of prime destinations. This is an issue which will be further elaborated in the further analysis.
While the spatial patterning of international migration has undergone significant changes, the relative number of migrants on a global level has actually decreased. While the absolute number of international migrants has increased from 93 million in 1960 to 167 million in 2000 – which is an 80 percent increase – the world population has actually grown faster from 2.98 billion to 6.07 billion, which is a 104 percent increase (UNPD, 2012). This explains why the proportional number of international migrants has slightly decreased from 3.1 percent of the world population in 1960 to 2.7 percent in 1980 to stabilize over subsequent decades (see Table 4 and Figure 1).
Table 4. Global migration intensity, spread, and distance, 1960–2000
Source: Authors' calculations.
Global migration rate (in % of world population)
Global migration spread (across 226*225 corridors)
Global migration distance (average in km)
While migration has not accelerated on a global level, there is some evidence of an increasing diffusion of migration. In Table 4, we estimate the global spread of migrants across all possible bilateral (country-to-country) migration corridors, calculated as one minus the sum of squares of the shares of the global migrant populations for each corridor in the world.4 This yields a measure ranging from 0 to 1; higher values would indicate that the global migrant population is scattered “relatively” equal across all migration corridors. Numbers show that the global migrant population is relatively unconcentrated with extremely high values between 1960 and 2000. Increasing values for this period indicate that the total world migrant population continuously spreads globally. Of the 50,850 bilateral corridors between the 226 countries and territories in our dataset, only about 32 percent were “filled” in 1960; this share has continuously increased to about 47 percent in 2000, which illustrates a growing connectedness between countries in terms of bilateral migration.5 In 2000, this number has increased to 23,674 “filled” migrant corridors . There is also some evidence that the average distance of migration has increased somewhat. Table 4 shows that the geographical distance covered by an “average migrant” (estimated by the distance between origin country and current country of residence) has increased from nearly 3,000 km in 1960 to over 3,600 km in 2000.
By calculating the reciprocity within bilateral migration corridors, we can assess whether over time within-corridor imbalances have increased or not. This is done through calculating bilateral net stocks, that is the number of people born in country j living in country i subtracted by the number of people born in country i living in country j, which indicates net movements per bilateral corridor (M2 stock; see Figure 1). Our dataset shows that in 1960, there was global migration imbalance across all migration corridors of about 57 million people. This means that about 61 percent of the global migration stock was not bilaterally balanced by an equally sized “counterstock,” but unidirectional. A respective “global migration effectiveness” ratio, which captures the aggregated net shift of people across borders relative to the global stock of migrants, has actually increased since 1960 by about nine percentage points reaching 70 percent in 2000.6 This suggests that global migration has become more skewed toward particular destinations attracting increasingly high numbers of migrants without being counterbalanced by significant reverse streams. In other words, there has been a decline in “migration reciprocity,” at least at the global level.
Global Spread of Migration
A next step is to differentiate between the spread of the global immigrant and emigrant populations in terms of origin and destination countries, respectively. We provide three different measures capturing three different reference points: First, the global emigrant spread (ISglobal) measures the extent to which the total global migrant population is dispersed across destination countries, while the global immigrant spread ISglobal indicates the extent to which the global migrant population comes from a diverse set of origin countries:
Calculation of these indicators reveals the distinct and diverging trends for the evolution of the global spread of emigrant and immigrant populations (Figure 2). While immigrant populations come from an increasingly diverse array of origin countries, they have tended to concentrate in an increasingly small number of destination countries. This reflects the earlier finding that the number of net immigration countries has decreased. In other words, a shrinking number of prime migration destinations attract migrants from an increasingly diverse array of origin countries.
The previous measures assess the spread of the world migrant population across destination and origin countries on a global level. On a country level, we calculate the emigration spread (ESi) and immigration spread (ISi), which, again using the Herfindahl index, indicate for each country i the extent to which bilateral emigrant (EMij) and immigrant populations (IMij) have become more diverse or concentrated across destination and origin countries, respectively.
The weighted global average of country-specific emigration and immigration spreads, respectively, is calculated as follows:
Figure 3 shows that on average (weighted at country level), immigrant populations have become less concentrated, which seems in accordance with the globalization of migration hypothesis. Also, national emigrant populations have become more spread across destination countries, although this increase has been lower than the growing immigration diversification. This finding, which shows that – at the country level – the emigration spread has also increased, may apparently seem to contradict the earlier finding (see Figure 2) that global migrant populations have tended to concentrate in a smaller number of destination countries. However, the global emigrant spread and average emigration spreads at country levels measure something different. While the former measures the extent to which migrants are spread across destination countries irrespective of their origins, the latter is the (weighted) average of country-level emigration spread values. What this means is that while from an individual origin country perspective, emigrants have gone to an increasingly diverse array of destinations, on a global level, these destination countries increasingly overlap; that is, they represent a decreasing pool of major immigration countries on which global migration has increasingly focused.
Furthermore, Figure 3 shows that over the past decades, immigration and emigration spreads have both increased. To a certain extent, this seems to confirm the idea of a tendency toward homogenization of global migration patterns. However, the spread of immigrant populations has increased far more than emigration spreads, which implies that while more countries have generated significant emigrant populations – which presumably reflects increased interconnectivity associated with globalization – “collectively” they tend to increasingly concentrate in particular destination countries. Country-level emigration patterns are increasingly resembling each other, with emigrants going to an increasingly similar set of dominant destination countries, such as the U.S., Germany, France, Canada, Australia, and the Gulf countries.
Regional Migration Patterns: Intensity, Spread, and Distance
The above findings suggest that the world has not become necessarily more migratory, but that migration has become more “skewed” on a global level. These findings challenge the hypothesis that there has been generic intensification of migration on a global level – presumably because of improving communication and transport links and globalization in general. It now seems useful to further look at the underlying regional trends to detect possible difference and changes in migration patterns which global averages are likely to conceal. For this analysis, we have used the UN classification of world regions and subregions as a basis to demarcate regions (see Table S7).
Figure 4 and Table S1 show considerable variation in the average size of country-level emigrant populations as a percentage of origin country populations. While emigrant rates have somewhat decreased in Europe and Africa, they have rapidly increased in Oceania and the Americas. However, there is considerable variation within regions. While Africa as a continent has relatively low and declining emigrant rates, on a subregional level, rates are relatively higher and somewhat increasing in Western and Northern Africa. While the Caribbean and Central America (including Mexico) have seen soaring emigration, levels are very low in North and South America. In Asia, emigration is high from the ex-Soviet republics of Central Asia as well as Western Asia, which includes most of the Middle East including Turkey, but is very low in the rest of Asia. In Europe, emigration levels have been particularly high in Eastern Europe and relatively low in Western Europe. In Oceania, emigration has been particularly increasing from Micronesia and Polynesia.
Looking at the reverse picture, we also find large variations across and within world regions for immigrant rates (see Figure 5 and Table S2). Over time, these have increased particularly in Europe and the Americas, remained more constant in Oceania, and decreased in Africa and Asia. Intra-regionally, immigrant rates have been particularly low in North African countries, but they have been higher in other parts of Africa, particularly Southern Africa. Thus, the poorer regions of Africa tend to have relatively low intensity of emigration and immigration. While immigration is high and increasing in Northern America, it has been decreasing in South America and is very low in the high-emigration countries of Central America. In Europe, immigration is high and increasing in all subregions, particularly in Western Europe. In Oceania, Australia and New Zealand and Micronesian states boast some of the highest immigration intensities in the world.
Also, when looking at the spread of emigrant populations, we see rather stark differences across and within world regions (see Figure 6 and Table S3). The Americas have seen a remarkable increase in the concentration (i.e., declining spread) of destination countries, which reflects the increasing focusing of emigration from Central America (particularly Mexico) to the U.S. For South and North America, these trends have remained rather stable. African emigrant destinations are remarkably spread, which primarily reflects a strong dispersion of migrants within the continent. Destination countries have been diversifying for North Africa, which partly reflects the rise of new European migration destinations beyond France, where most migration from the Maghreb used to concentrate. European emigration is also highly spread, which mainly reflects migration within the continent and less extra-regional outflows. Asian emigration has become more spread, which primarily reflects increasing diversity of migration from Central Asia.
Compared with the rather mixed picture in the spread of destinations for countries' emigrant populations, we see a clear-cut trend toward highly spread immigrant populations in terms of origin countries, particularly for Oceania, Asia, and, to a lesser extent, Europe (see Figure 7 and Table S4). Increasing diversity of Asian immigration populations primarily reflect migration from an increasingly diverse array of origins to Southeast Asia (Singapore, Brunei, Thailand) and East Asia (Hong Kong, Japan, South Korea, Taiwan). Increases in immigration spread in Oceania mirror growing immigrant spread in Australia, New Zealand, and Micronesia. In Europe, increasing spread of immigrant populations has primarily occurred in Western and Eastern Europe. For immigrant populations in African countries, spreads of origin countries have remained on a consistently high level, largely reflecting strong intra-continental migration. In the Americas, immigration spread has been slightly decreasing, although this is mainly the result of decreasing immigration diversity in Central America.
Figures 8 and 9 (see also Tables S5 and S6) display that patterns of average migration distances by emigration and immigration countries also show considerable variation. They are highest in Oceania, which is linked to their geographical seclusion. They are lowest in Africa but have been increasing, particularly from Southern and Eastern Africa, partly reflecting increasing migration to Western countries. Average emigration distances have been increasing in South America, while they remained constant in the Caribbean and Central America. Average distances travelled by migrants leaving from Southern and Eastern Asia have rapidly increased, while they have stagnated or decreased elsewhere in Asia. In Europe, emigration distances have decreased with diminishing migration out of Europe.
Looking at immigration distances, we see a decrease for Oceania, reflecting declining European and increasing Asian immigration. Also, in South America, there has been a huge decrease in average immigration distance, reflecting plummeting European immigration. Only in North America, there has been a slight increase, primarily reflecting a strong increase in Asian immigration. In Asia, immigration distances have been particularly increasing in the wealthy countries of East Asia and have actually declined in Southeast Asia. Average immigration distances have been decreasing in Africa, with the exception of North Africa.
Migration Globalization at the Country Level
To further explore the hypothesis on the globalization of migration at the country level, we want to combine measures of a country's level of dispersion of its emigrant population and the level of diversification of its immigration population. Therefore, we propose a methodology for a Migration Globalization Index (MGI), which is an index that combines two composite subindices, the Emigration Dispersion Index (EDI) and the Immigration Diversification Index (IDI):
These two subindices are geometric means with equal weights of respective measures on intensity (EI and II), spread (ES and IS), and distance (ED and ID).7 Both subindices are scaled from zero to one, making straightforward comparisons between the EDI and IDI scores possible. Finally, the Migration Globalization Index (MGI) is then calculated by the geometric mean of the EDI and IDI scores
which indicates a country's level of “integration” into global migration processes.
In the following, we will present some key results of the analysis and provide interpretations of the evolution of the global pattern of migration at the country level.
A first key observation is that small states and territories have the highest degrees of migration globalization, indicating that countries and overseas territories with small populations are much more prone for migration than more populated countries. Across four decades between 1960 and 2000, about three quarters of the top 20 most “migration-globalized” countries were small, defined as having a population of less than 500,000 in 1960. According to this definition, about a third (76 of 226) of all countries and overseas territories in the database were small in 1960. Small countries are similarly overrepresented in both emigration dispersion and immigration diversification. The set of small countries with high levels of emigration dispersion, however, look rather different from the set of small countries hosting a highly diversified immigrant population. At the top of the most dispersed populations, we find small, mostly developing islands as “migrant sending states” such as Cape Verde, Samoa, or Suriname, whereas the distinct group of small countries with an often highly diversified immigrant population are among the wealthiest in the world such as the Gulf countries (Qatar, Kuwait) or places known for affluent lifestyles (the Cayman Islands, Monaco, Bermuda).
This finding supports the existing idea that geographically large and more populated countries are likely to capture more migration within their own borders. In small countries, many migrations become international that in larger countries would have counted as “internal” migration. This seems to particularly apply for countries which lack urban agglomerations where particularly skilled workers tend to find employment, increasing the likelihood that what is essentially rural–urban migration involves border crossing (cf. de Haas, 2010).
As our rankings are skewed by this “small country bias,” we may consider the larger set of non-small countries separately, which are by our own definition those countries with a population size of more than 0.5 million in 1960. Figure 10 displays EDI and IDI scores for the top 10 non-small countries, ranked by their average MGI score across 1960 and 2000. Unsurprisingly, we see some “classical” immigration countries such as Australia, Israel, or Canada and “long-term” emigration countries such as the UK, Portugal, or Lebanon at the top of this list. Aggregation of the EDI and IDI scores, which generates MGI scores, shows that for all of these top 10 countries, their degree of integration into global migration has continuously increased over the past decades.
Additionally, this sample of the most migratory (non-small) countries of the world suggests a negative relationship between levels of emigration dispersion and immigration diversification – higher levels of immigration diversification are associated with lower levels of dispersion of emigrant population. This pattern, however, is not representative and globally robust. In fact, when we consider all countries and territories of the world, the process of emigration dispersion is rather positively associated with immigration diversification; this relationship only weakens at the high end of the immigration diversification scale. Figure 11 separately displays for small and non-small states that IDI scores relate positively to EDI scores. This positive relationship is even stronger and more robust (smaller variance) for non-small countries. This implies that immigration diversification and emigrant dispersion processes are dynamically integrated and coevolve over time, in particular for non-small countries. This finding is in line with migration systems theory.
Figure 12 highlights several aspects of the globalization of migration processes at the country level. First, emigration dispersion levels are systematically lower than levels of immigration diversification both on average and over time. Second, emigration dispersions have become more leptokurtic (“spiky”) over time. This implies that – from an origin country perspective – the “diversity of destinations” has slightly decreased over the past decades. Although more countries have integrated in the global migration systems, the level of dispersion of countries' emigrant population across destinations has somehow decreased. Third, immigration diversification has become more platykurtic (“flatter”) over time, which means that the level of immigration diversification has significantly increased. This indicates to a growing “diversity of origins” from which a less diverse set of global destinations receive their immigrant populations from.
Which are these countries with a high level of immigrant diversification? Figure 13 displays global maps indicating countries by their levels of immigrant diversification, and the extent patterns have changed between 1960 and 2000. While in 1960, global migration map is still dominated by the aftermath of the trans-Atlantic migration systems connecting European-origin states with Northern and Southern American destinations, the world in 2000 looks slightly different. New destinations have emerged as poles of attraction for a rather globalized population of immigrants such as the Gulf region (UAE, Saudi Arabia, Oman, and Kuwait) and Western Europe (Portugal, Sweden, Norway, Denmark, and Spain), while some “older” destinations lost some of their attraction (such as Argentina, Uruguay, and Venezuela in Southern America or Zambia, Angola, Madagascar, and South Africa in Southern Africa). We can even say that the array of global migration destinations has “northernized,” which has partly to do with a growing attractiveness of European, North-American, and other wealthy destinations, and declining migration and settlement in Latin America and Africa, in particular.
A different pattern has emerged when looking at processes of emigration dispersion, which combines measures of emigration spread, intensity, and distance (Figure 14). In 1960, European and some African countries were the major origins with an emigrant population widely dispersed beyond the respective continents. For African emigration, this has since changed slightly due to a growing importance of intra-continental destinations, although overall levels of emigration dispersion in Africa have remained rather low. Between 1960 and 2000, Malawi, the Republic of Congo, and Burundi dropped significantly in the list of countries with a highly dispersed emigrant population. The character of European emigration also changed over this period. While transcontinental migration lost in relative importance, intra-European migration has gained weight in the dispersion of European migrants. For instance, Spain, Italy, Belgium, and Austria are among the countries globally with the strongest decline in the level of dispersion of their emigrant populations, which reflects declining extra-continental and increasing intra-continental migration.
At the other end of the spectrum of emigration dispersion levels, small island economies have experienced very high levels of outflow and globalization of their emigrant populations. No matter whether we consider Polynesian islands (such as Samoa, Tokelau, Tonga, or Tuvalu), Caribbean islands (Guadeloupe, Montserrat, or Netherlands Antilles), or East and West African islands (Saint Helena, Reunion, Seychelles, or Sao Tome and Principe), all of these islands have gone through a period of transition that has dispersed a large portion of their population to other island states in the region (e.g., in Oceania) or to economies farther away that provide more opportunities.
Evaluating processes of emigration dispersion and immigration diversification jointly by the means of the Migration Globalization Index, the world in 2000 looks like a patchwork (Figure 15). It shows regional migration hubs which receive a highly diverse immigrant population – mostly from the same region but also and increasingly from all over the globe. These hubs, however, are also places from where people disperse all over the world. Such regional and global migration hubs are surrounded by countries that are weakly or moderately integrated into global migration systems. From those countries, migration flows tend to be unidirectional oriented toward regional hubs. An exchange of people between these hubs and their respective periphery thus hardly exists. Finally, there is a range of countries located mostly in Asia (Bangladesh, North Korea, Nepal, Myanmar, Mongolia), Africa (Algeria, the Central African Republic, Burundi, Ethiopia), and Latin America (Haiti, Colombia), which are neither important migration destination nor origin countries, at least until recently. This low level of global migration integration sometimes reflects politically chosen isolation or “self-exclusion” (such as for North Korea), but can also coincide with historically low levels of economic and human development and global integration. This seems to reflect the category of countries which Skeldon (1997) called the “resource niche,” that is, countries characterized by comparatively low levels of integration into global or regional migration systems.
The preceding analyses challenge the common idea that there has been a global increase in volume, diversity, and geographical scope of migration. While international migration has not accelerated on a global level, main shifts in global migration have been directional and are linked to major geopolitical and economic shifts, the concomitant rise of new migration hubs in Europe, the Gulf, and Asia, development-driven emigration hikes in origin countries, and the lifting of emigration restrictions in former Communist and developing countries. This underscores the critical importance to embed the rigorous analysis of international migration patterns into broader analyses of economic and demographic change (cf. Skeldon, 1997; Coleman, 2006; Castles, 2010).
This article showed that the idea that immigration has become more diverse may partly reveal a Eurocentric worldview. While immigrant populations have become more diverse in new destination countries in Europe, this is not always the case elsewhere, such as the Americas and the Pacific, where immigrant populations have become less European but not necessarily more diverse in terms of diversity of origin countries. For instance, while immigration countries such as the U.S., Canada, Australia, and New Zealand used to attract Europeans, non-European immigration has been surging since the 1960s. Some Latin American countries have seen decreasing diversity coinciding with their transformation from immigration to emigration countries.
With declining European emigration toward other continents, there has been major shift in global directionality of migration, with the transformation of Europe from a global source region of emigrants and settlers into a global migration magnet. This has led to an increased presence of phenotypically and culturally distinct immigrants in Europe as well as settler societies of European descent in North America and the Pacific. In other words, rather than an increasing spread in terms of origin countries of migrants per se, the national and ethnic origin of immigrant populations has become increasingly non-European.
It is a key observation from our analyses that migration has “globalized” from a destination country perspective but hardly from an origin country perspective. This implies that migrants from an increasingly diverse array of non-European-origin countries have been concentrating in a shrinking pool of prime destination countries. The global migration map has thus become more skewed.
Several factors may explain immigration diversification. First, over the past decades, many former Communist and developing countries have lifted restrictions on the emigration of their citizens (Zolberg, 2007; de Haas and Vezzoli, 2011), enhancing access to international migration opportunities. For instance, the collapse of Communism has contributed to the diversification of immigrant populations in Western Europe. This has been part of a more general ideological shift toward economic liberalization, in which emigration and remittances have come to be seen as potential engines for economic growth (Castles and Wise, 2007).
A second major factor seems the development process itself. Over the past decades, many developing countries have experienced emigration hikes as they entered a “migration transition.” As infrastructure, education and living standards have improved in most countries in the world, more people than ever have the capabilities to migrate. Education alongside radically improved access to media such as satellite television and Internet may have also increased awareness of opportunities elsewhere, increasing people's migration aspirations. Such development-related increases in migration capabilities and aspiration may explain why development initially tends to coincide with accelerating emigration (Zelinsky, 1971; de Haas, 2010; Skeldon, 2012).
Other factors may include the decreasing significance of post-colonial migration patterns. In the 1960s and 1970s, migration from many developing and former colonies tended to be concentrated on the former colonizers (e.g., from the Maghreb countries to France; or from Guyana to Britain) because of economic, social, cultural, and linguistic ties. These ties may have eroded over time, possibly coinciding with a diversification of migration. Another factor may be that immigration policies of classical immigration countries often tended to select based on national origin or race and ethnicity. In recent decades, such criteria have often been weakened (e.g., the abolishment of the “White Australia” policy in 1972), along with an increasing selection based on skills or income of potential migrants.
So, the diversification of immigrant populations in terms of their origins seems partly related to decreasing emigration restrictions, the shifts toward skill-selective immigration policies, the waning of post-colonial effects, and development-driven migration transitions. On a more general level, since 1960, increasingly more countries have become incorporated into the global economy, a process that has been facilitated by technological progress and a general liberalization of economic policies. As part of this process, a growing number of countries have entered the global “migration market,” increasing the global pool of potential origin countries. There is a shrinking pool of countries left that remain marginally integrated in global economic and migration systems.
This article has observed an essential paradox: While most countries now generate significant emigration, the total volume of international migration has not increased in relative terms, whereas migrants tend to concentrate in a shrinking number of prime destination countries. Also, while the number of empty migration corridors has decreased, migration has tended to concentrate in the larger corridors. This seems to contradict some key hypotheses of the globalization of migration paradigm.
With regard to the non-acceleration of global migration, several researchers have ascribed this to growing immigration restrictions. The argument is that while state policies have promoted trade and capital flows, most states have reinforced their control over migration and that migration would therefore have been excluded from globalization processes. Analyzing data from 1965 to 1995, Tapinos and Delaunay (2000) indeed found that migration has not accelerated at a pace comparable to increases in capital flows and trade in goods and services.
Yet it is unlikely that immigration restrictiveness can largely explain this paradox. First, there is reason to question the very assumption that there has been a generic increase in immigration policy restrictiveness over the past decades. Rather, levels of restrictiveness have tended to oscillate with economic cycles and political–ideological shifts. Immigration policies have increasingly been about selection migrants in terms of their national origin, occupation, and wealth, rather than about curbing volumes per se (Ortega and Peri, 2009; Czaika and de Haas, 2013). Because immigration rules are often simultaneously constraining and facilitating migration of different national, occupational, or family groups, it becomes even debatable whether it is useful to talk in terms of general policy restrictiveness at all.
Second, the assumption of growing migration policy restrictiveness reveals a destination country bias and overlooks the fact that many developing and former Communist countries have lifted exit restrictions over the past decades and that an increasing numbers of states have started encouraging emigration, particularly of the lower skilled (cf. de Haas and Vezzoli, 2011). So, the presumed migration-decreasing effects of increasing entry and residency restrictiveness for some migrant categories (particularly low-skilled labor migrants) have at least been partly counterbalanced by the migration-facilitating effect of decreasing exit restrictions. In this context, Zolberg (2007) speaks of a “tug-of-war,” in which poorer states have sought to prevent the emigration of “valuable population” (generally the highly skilled) and welcome opportunities to “shovel out” the surplus of low-skilled labor, while richer states increasingly favor immigration of the highly skilled while being less prone to favor legal entry of the lower skilled.
Third, a focus on policy restrictiveness as an explanation may potentially overrate the relative importance of migration policies as a migration determinant. The degree to which policies can actually control migration is limited and conditioned by larger economic and political forces driving migration (Castles, 2004; Cornelius et al., 2004; de Haas, 2011).
There, however, seem to be other, more fundamental reasons why technological and economic globalization has not coincided with an acceleration of migration. First, from a theoretical point of view, the impact of technological change on migration is ambiguous. While advances in communication and transport technology facilitate movement, this does not necessarily lead to more migration, because technology can also allow people to stay at home. Potential migration can be absorbed by circulation because of improvements in transport technology allowing for long-distance commuting, while potential circulation and commuting can be absorbed by communication systems allowing people to work from home (cf. Zelinsky, 1971; Skeldon, 2012). Technology also facilitates trade, capital flows, outsourcing and offshoring of production, and Internet-based teleworking, which seem to have spurred non-migratory forms of mobility such as commuting, tourism, business trips, and short-term international assignments. So, while this has made the world more mobile, it has not necessarily made the world more migratory.
As this article is based on migrant stock data, it was not able to explore whether globalization has increased with an increased “turnover” of migration as a consequence of a higher incidence of temporary and circular migration. While this may be true for migration between countries in free-mobility areas such as the European Union, there is also growing evidence that immigration restrictions reduce circulation. In a recent study on the short- and medium-term migration dynamics based on flow data, Czaika and de Haas (2014) show that barriers to migration such as immigration restrictions can severely reduce the responsiveness of migration to business cycles and thus decreasing overall levels of circulation and encouraging long-term settlement. This casts doubt on the assumption that overall circularity has increased.
Finally, how can we explain that global migration patterns have become more skewed with migration from an increasingly diverse array of origin countries concentrating on a shrinking pool of prime destination countries? A plausible explanation for the growing skewness of migration under conditions of globalization is that we have misunderstood the very nature of globalization processes. Although it is often argued that processes of technological progress and growing interconnectivity have “flattened” the world (cf. Friedman, 2005) and made global opportunity structures more egalitarian, in reality, contemporary globalization has been a highly asymmetrical process, which has favored particular countries – or rather cities and agglomerations within countries – and social, ethnic, class, and professional groups within them, while simultaneously excluding or disfavoring others (Sassen, 1991; Castells, 1996; ECLAC, 2002). Although various parts of the world are more connected than ever, in many ways, the world has become less flat, for instance through rising income inequality between and particularly within countries (Stiglitz, 2006). Florida (2005) argued that although globalization has changed the economic playing field, it has not leveled it. Looking at the maps of location-specific global resource distribution, the world has remained invariably “spiky,” with most economic activities concentrated in a relatively low number of countries and, particularly, places (Florida, 2005).
In the same vein, liberalization and globalization processes seem to have increased access of people living in poor countries to the international migration “game,” and it has not made the playing field more level, rather the reverse. This shows that migration globalization is not a natural, inevitable process semi-autonomously driven by technological change, but primarily the result of political and economic shifts. Human resources and economic activities have become increasingly concentrated in a relatively low number of countries or, more precisely, metropolitan areas within a few countries – which reflects processes of urbanization and internal (rural–urban) migration. According to Florida, the main difference with a few decades ago is not that the world has become “flatter” but that the world's economic peaks have become geographically slightly more dispersed, particularly as a consequence of fast economic growth in East Asia.
Within this critical view on globalization, migration can be seen as one of the key dimensions of the highly unequal global terms of exchange. This is also reflected in migration policies that give employment and residence rights to certain favored (generally skilled and/or wealthy) groups, but at the same time exclude lower skilled migrants from such rights. These exclusion mechanisms do not stop migration but are likely to make migrant workers more vulnerable to exploitation on the labor market. Thus, the highly skewed spatial impacts of globalization also seem to be reflected in shifts in global migration patterns. Rather than refuting the globalization of migration hypothesis, this seems to reflect the asymmetric nature of globalization processes in general.
The GBMD has its origins in the pioneering work carried out at the University of Sussex and was later expanded by the World Bank and the United Nations Population Division (see Parsons et al. (2007)).
This may partly reflect colonial settlement or, such as in the cases of Turkey and India, processes of state formation.
This measure is the Hirschman–Herfindahl index on migrants' concentration in bilateral corridors. As we are rather interested in an indicator of spread (and not of concentration), we subtract the concentration score from 1.
See Bell et al. (2002) for the definition of an index of migration connectivity: . In 1960, 16485 of 50850 possible bilateral corridors between 226 countries have seen positive migrant stock .
See Shryock et al. (1975) for a general definition of “migration effectiveness.”
Geometric aggregation ensures limited compensation (substitutability) between its components. This ensures, for instance, that for a country with no immigration at all, that is, an immigration intensity of zero, the respective Immigration Diversification Index is equally zero (and not positive). Furthermore, weighting of components (subindices) is a crucial decision in the compilation of any index. For the EDI and IDI, we use equal weights for all three dimensions, which is supported by the fact that rank robustness of each index is rather high. This implies that any alternative weighting scheme does not lead to a strong change or even reversal of the overall rankings (see Czaika, 2013).