Highly-Skilled Migrants in the Transatlantic Space: Between Settlement and Mobility

In this chapter we look deeper into the specific case of Global Northerners who migrate within the Global North. Their case is used as an illustration of the complexities of highly skilled migration; these complexities impact lives of even the seemingly privileged mobile skilled people moving within the trans-Atlantic space of freer movement. At the heart of our discussion is an examination of the tension between settlement and mobility.


Transatlantic Migration System -A Case Study
In this chapter we look deeper into the specific case of Global Northerners who migrate within the Global North. Their case is used as an illustration of the complexities of highly skilled migration; these complexities impact lives of even the seemingly privileged mobile skilled people moving within the trans-Atlantic space of freer movement. At the heart of our discussion is an examination of the tension between settlement and mobility. On one hand, transatlantic migrants might have an easier time migrating than do Global Southerners because of specific privileged policy channels; on the other hand, they might also find it difficult to settle and they may return. Patterns of settlement and mobility are thus related to integration challenges which define North-North migration as much as any other migration. In our view, this case can serve as a broader generalisation about the experience of the highly skilled migrants (Box 4.1).
To present our case study, we offer a general picture of highly skilled mobility over the Atlantic, then discuss mobility and integration drivers that influence this migration; and finally we discuss the integration outcomes of this particular group of migrants and the impact this migration has on the countries of origin and destination. Since it is North-North migration we go beyond the "migration and development" discourse, shedding the light on the challenges of economic measurement in the intertwined economies.

Emerging Patterns of Mobility: The Case of Transatlantic Migrations in Twenty-First Century
Migration studies today is largely based on an academic analysis of the transatlantic migration flows in the nineteenth and early twentieth centuries. The nascent field documented the arrival and settlement of millions of people from all over Europe, with various skill levels, making North America their home. Despite such publications as Mabogunje's 1970 system theory of migration, which also addressed skilled migration, with a focus on Africa, as well, the image of the immigrant as a permanent settler has defined perceptions of international migration well into the twentyfirst century. Some research suggests that this image of the one-way, permanent immigration flow may be at least partially mythical with far higher rates of return Box 4.1: Expats no More? Recent research has moved beyond studying highly skilled migrants solely as a particular group of "expatriates" coming from the Global North, forming a sort of a "global super-class" or "transnational elite" of "self-initiated global careerists" (Ho 2011;Brimm 2010). While there certainly are migrants who fall into this category of very highly remunerated global elite migrants, we take a more critical stance towards this particular group here, noting that this group is becoming proportionally smaller than all other groups of highly skilled migrants, many of whom come instead from the global middle class (Conradson and Latham 2005;Ball and Nikita 2014;Rutten and Verstappen 2014). These highly-skilled migrants might just not be "masters of the free movement" (Smith and Favell 2006), as they were once called; they do not necessarily enjoy unprecedented liberty, mobility and recognition, even when compared to low-skilled migrants. They also have more to lose in terms of three forms of Bourdieu's capital. They are, literature increasingly seems to suggest, not as different from low-skilled migrants as they once were seen; rather, their gender, ethnicity, education, country of origin and migration destination may well play a stronger role in defining their migration trajectory and outcomes (Meier 2014).
that generally thought (Gabaccia 2013;Portes et al. 2003Portes et al. : 1215Klekowski von Koppenfels 2014). Regardless of the extent to which the image of the permanent one-way migration from Europe to North America was reality or myth, these dynamics do change and, indeed, these changes are most visible in what is perhaps the longest studied migration system in the world. The transatlantic migration system of today, at the beginning of the twenty-first century, does not resemble the system we knew 100 years ago. It is characterized by three main dynamics: decrease of migration flows and increase of short-term mobility; an increase of the average skill level of a migrant; and the rise of bi-directional migration and mobility. 1 Of the immigrants to the US and Canada, the number of those who originate from Europe continues to shrink. 2 This is the sign not only of the growing numbers of migrants from other destinations, but also of dropping interest in transatlantic settlement among Europeans, especially from the European Union/EFTA/EEA countries. 3 An overview provided by the Migration Policy Institute has found that the total number of European Union-born immigrants in the US has decreased since the 1960s (Sumption and Hu 2011), while Weinar reached the same conclusion for the Canadian case (Weinar 2019). In general, Europeans apply less for permanent residency and their migration strategies no longer reflect intended. These characteristics do change from country to country, both of origin and destination. And thus, in the US case, there is no clear distinction between EU-15 or EU-12: in all groups there are countries with higher and lower numbers of permanent emigrants (Sumption and Hu 2011). This dynamic is quite different in the case of Canada, where the EU-15 are more likely to immigrate to Canada than the EU-13 (Weinar 2019).
However, lower numbers of permanent, settlement migration does not mean that overall mobility has fallen. In fact, a high share of Europeans still come to North America, but rather as temporary migrants. Sumption sums them up as scientists, managers, and tourists. These three categories reflect the main streams of entry: as workers in the knowledge economy (scientists and researchers); temporary workers in skilled positions; tourists. To this group, MPI added students, the number of which has increased over the last two decades. A closer look into the administrative data shows that EU citizens have been more prone to temporary migration since the 1980s. Their overall share has fallen, but they still keep their dominance in some categories of temporary work programs. For example, as noted by Sumption, "in 2005 EU-27  most elite temporary work visas for individuals with "extraordinary ability" in the sciences, business, or arts (the O-1 visa). By 2009 Europeans' share of H-1B and L visa issuances had fallen slightly (to 10% and 23% respectively), but their share in O-1 visas has remained unchanged." (2011, p. 9).
A similar trajectory can be found in Canada. Most of the European Union citizens entering the country come as temporary migrants in just two programs: 52% in the International Mobility Program (for cultural and scientific exchanges and work and travel program IEC -International Experience Canada), and 19% are students. In fact, well over 42,700 EU nationals qualified for IEC in 2014 alone. Similar trends have been observed in the US (ESSQR 2014).
The stream for permanent residency was 20% of the total mobility, and came mostly from economic migration of skilled workers. Indeed, in 2016, the British, French, and Irish figured prominently among the top ten nationalities of Express Entry invitees, a program targeting highly skilled immigrants for permanent residency. Together they constituted 11% of all ITAs recipients. Under the Canadian point system, in that year the program privileged, through the assignment of maximum points, previous employment relationship applicants had Canadian employers or job offers in hand. In 2017, when the existing employment relationships in Canada and existing Canadian job offers were downgraded in the criteria (obtained fewer points), members of those same nationalities received only 5% of all invitations. The high share from 2016 is directly related to the quite high temporary migration of EU nationals to Canada, who come to the country on visitor visas or temporary work permits and thus have a chance to establish employment relations in Canada. This in turn, in 2016 at least, gave them heads-up in the Express Entry applications.
The most important take-away from the data analyzed both by Sumption and Weinar is that mechanisms of international mobility have replaced settlement migration in the transatlantic migration system. In the twenty-first century so far, temporary mobility has been double or triple the volume of the mobility for permanent residency, with over a million EU nationals engaging in various forms of temporary work or study in the US and Canada every year.
This data also attests to the fact that Europeans nowadays might have more social, financial, or human capital in order to make this immigration happen. But they also testify to the specificity of the transatlantic migration system in the twentyfirst century, which has been transformed in a space of mobility.

Drivers of the Contemporary Mobility in the Transatlantic Context
In the view of growing globalization, since the mid-1990s scholars have been announcing the end of the nation-state, presumably weakened by globalisation. Sassen's "losing control" thesis concluded that the State can no longer fully control its borders (Sassen 1999). Two decades later the nation-state is back, with a vengeance. The nation-state is seen by some as the dominant actor in an international network that organises lives of individual people, citizens or not, by recreating the sense of belonging and translating it in freedom to move enshrined in identity documents and a variety of rights coming with them (Torpey 2000;Brubaker 1992). In the domestic context, the state is viewed as a guardian and guarantor of a rights framework (Bommes and Geddes 2000;Mau et al. 2012;Cholewinski and Taran 2009) while market powers are perceived as disruptors of this framework. From a point of view of immigration policy, the state is there to assure the rules of admission to the internal labour market and the rights framework for the workers. As the overarching institutional framework/actor entitled to use force, the state is also responsible for protecting own citizens against social dumping and unfair competition on the labour market (Coldron and Ackers 2009;Schmidt 2002). In many cases, it has an obligation to discriminate in favour of its own citizens. The key instruments the state has at its disposal to find the balance between these contradicting interests are the entry and residence regulations (hard barriers) and labour regulations understood as regulation of qualifications, skills and other requirements (soft barriers) (see also Chap. 3).
The intricate web of barriers and gateways is nowhere as evident as in the case of the modern transatlantic migration system. Over the last 50 years the states on both sides of the Atlantic have intensified collaboration in all spheres, built trade interdependence and gradually removed a number of barriers to mobility of the respective passport holders. Highly skilled migrants are one of the migrant groups and their rights are strictly related to the legal framework governing mobility within the transatlantic space, and most notably: to the power of their passports or what Spiro calls "premium citizenships" (Harpaz 2015). In what follows we discuss four groups of migrants, defined according to the number of hard and soft barriers to their mobility.

Open Border Migrants
This group is comprised of the citizens of the economic/political region of the European Union, who automatically gain mobility rights by holding the citizenship of another EU member state. Foreigners in this group can be called insiders, because their rights are on a par with the rights of citizens of the given member state. All hard barriers are removed for them, such as labour market access rights and welfare rights (long-term residence is contingent upon employment). Moreover, the soft barriers to their mobility are attenuated, based on multilateral or bilateral agreements which cover automatic recognition of educational credentials (thanks to the Bologna Process), clear rules of recognition of qualifications in regulated and nonregulated professions (thanks to EU-level legislation, e.g. Directive 2005/36/EC) and related mobility. Post-2008 economic crisis, migration from Southern to Northern Europe increased substantially (Lafleur and Stanek 2017), identifying both facilitation of recognition of qualifications as well as limitations (Klekowski von Koppenfels and Höhne 2017, pp. 167-8). Still, this internal group has not been open to all the countries in the transatlantic migration system and remains limited to the EU (Box 4.2).
EU labour mobility delivers benefits for both sending and receiving countries. In a long-term perspective with increasing return flows, the distinction between sending and receiving can become blurred. With return flows being facilitated, diminishing regulations and enforcing mutual recognition, the original sending countries may benefits from present remittances whilst expecting future knowledge and innovation to come through returnees. Receiving countries enjoy a pool of talents to count on in booming times. This ensures that the business cycle avoids bottlenecks.
Rights of this insider group can be extended to non-EU passport holders under certain conditions inscribed in the immigration legislation of the EU and more specifically as regards Long Term Residents (LTRs), refugees and Blue Card recipients. This means that US citizens and Canadian citizens can only achieve full mobility on par with EU citizens when they become LTRs or Blue Card holders (refugee status is irrelevant in this case). However, a legal framework allowing for open borders, as in the EU, does not exist in North America.

Semi-open Borders Migrants
Aside from visa-waiver/visa-free entry between North America and (most) EU states, there is no legal framework that benefits European passport holders when emigrating to North America and vice versa. However, a number of arrangements do facilitate mobility and thus give a certain advantage to the transatlantic passport holders. States on both sides of the Atlantic have developed a number of channels to facilitate such entry for respective citizens, although the framework is not allencompassing and we can see a patchwork of bilateral and multilateral arrangements.
What we might call the semi-open borders migrant group is comprised of citizens of the EU, US and Canada. Most of them (enjoy visa-free access to each other territory as visitors (business, tourists or job-seekers) for minimum 90 days (Weinar

Box 4.2: Intra-EU Mobility
Freedom of movement might be a double-edged sword in the transatlantic context. As research by Dominique Gross (2012) shows, when in 2002 Switzerland applied the EU freedom of movement, the policy had adverse effect on the size of high-skill immigration from North America. The priority given to Swiss and EU citizens pushed many highly skilled professionals to consider professional networks and financial opportunities back home. The consequent limitation of geographical heterogeneity in immigrants can be detrimental to Swiss businesses. 2019; Sumption and Hu 2011). Moreover, some other hard barriers to mobility removed: e.g. the States assure their preferential treatment on the basis of the new generation of trade agreements (e.g. CETA) or special political relationship (e.g. Quebec and France); the States have built a network of agreements facilitating mobility of students and researchers (e.g. Fulbright-Schuman fellowships or the DAAD fellowship scheme). Citizens of the countries with special relationship gain automatic access rights to the labour market on stipulated terms, without quotas. It is notable that the transatlantic migration system is the one with the most work and travel agreements in the world (Weinar 2017).
The role of trade relations for this migrant category cannot be overstated. Increased economic relationships, with businesses active on both sides of the Atlantic, predominantly drive mobility of these skilled migrants. Most recently, the EU-Canada Comprehensive Economic Trade Agreement (CETA) devoted a whole chapter to the mobility of temporary workers. Chapter 10 of CETA provides for enhanced mobility for contractual services suppliers, independent professionals, and business people visiting for investment purposes, investors, and intra-corporate transferees (which includes senior personnel, specialists and graduate trainees). It does not preclude the use of the visas (Art. 10.3(3)), but it insists on a facilitated and reasonably quick way to get the documents needed in order to move. In effect, it states, the immigration procedures for the citizens of the parties to the agreement shall be prioritised, not to endanger the trade relations. Annex 10-E outlines over 50 sectors in which the mobility of service suppliers and independent professionals is to be facilitated. It also includes a long list of exclusions, almost entirely from the EU Member States, concerning labour market access, primarily related to the requirement of a labour market test, a rather standard, yet time-consuming procedure. The agreement looks quite unbalanced from this perspective, given that Canada includes nearly no exclusions.
In the semi-open borders scenario, the illusion of open borders is quickly dispelled when the migrants encounter the "soft barriers" to the labour market access and access to rights. These barriers usually keep the migrant workers in pre-defined sectors and occupations. However, in the transatlantic case, there have been clear attempts to remove these barriers. Chapter 11 of CETA invites parties to work towards the mutual recognition of qualifications. The language from this chapter has been modelled after the France-Québec Agreement on the Mutual Recognition of Qualifications (MRA). It sets out a general framework, detailed in Annex 11-A, on how to approach this. Recognition of qualifications has been facilitated also in other instances: Quebec-France MRA, or mutual understanding achieved by the professional bodies through decades of cooperation. In the first case, over 160 regulated professions and trades have had clear translation schemes established for them ). Thanks to the agreement, skilled French workers (permanent and temporary) experience shorter delays in pursuing their profession in Quebec. The agreement minimises the likelihood of deskilling for French citizens, and thus prevents the brain-waste in the event they return to France. In the second case, the qualifications of many UK-trained professionals are recognized more easily in Canada or the US thanks to the organic work of professional bodies of the two jurisdictions that span decades of bilateral relations (Iredale 2001;Weinar 2019).
Finally, migrants in this group benefit from a dense net of treaties which avoid dual taxation and which support combined approach to social security (Sumption and Hu 2011). Overall, we can say that the arrangements in place, albeit not encompassing all countries in the transatlantic migration system equally, create a sphere of increased mobility, especially in the short-term.

Selected Temporary Migrants
Transatlantic migration system also has a number of exclusions. The selected migrants group is made up of citizens of the other countries, outside of the EU/US/ CAN system. The decision to allow for more mobility rights is usually limited in scope and can take a form of a unilateral policy or bilateral arrangement (proposed however by the receiving country). The programs allow for entry of temporary workers under very specific conditions, often within set quotas. Their entry to the labour market is narrowly defined and thus "hard" and "soft barriers" create a secondary class of migrants. All temporary worker programs for low-skilled migrants fall in this category, e.g. in the EU we are talking about seasonal migration, in the US and Canada: temporary workers in agriculture. Yet, highly skilled workers are also a part of the temporary foreign workers stream, e.g. as H1B visa holders in the US or International Mobility Program beneficiaries in Canada. Their presence is however less visible and not mediatised.
There are also a number of educational exchanges between Europe and the United States, including Fulbright, DAAD (German Academic Exchange Service) and many others. These are, however, often conceptualized as programs for cultural understanding rather than explicit training or temporary high-skilled worker programs. Nonetheless, as having lived abroad is a predictor for aspiring to live abroad again (Marrow and Klekowski von Koppenfels 2020: 28), such programmes do contribute to future mobility.

Closed Borders
The closed borders of the transatlantic system is the reality faced by the majority of the world population. Mobility under these circumstances is impossible. Permanent migration pathways are open to a small share of potentially interested individuals in North America, and inexistent in Europe, as all legal immigrants to European Union are initially temporary migrants, but can transition to a permanent status. Those who cannot make it through the bottlenecked legal channels try other ways in. As a result, undocumented flows of migrants then become vulnerable migrant workers, exploited or even enslaved (Bales 2012;Callister et al. 2006). Only few EU/US/ CAN citizens emerge in this group (Weinar 2019;Sumption and Hu 2011) perhaps particularly so in the case of bilateral flows between European Union and North America, although some migrants from the Global North may well be undocumented.
Drivers of mobility in the transatlantic migration system are thus related to economic and political cooperation that has developed in this area over the last 100 years. The transatlantic migration system is organised by state power networks that regulate mobilities of citizens within them (Krahmann 2005;Paár-Jákli 2014). The ascent of the European Union with its bold ideas of open borders for goods, services and people has influenced the bilateral policies. The idea of beneficial influence of people-to-people contacts and profits brought by mobility of certain workers to the transnational businesses has shaped the transatlantic space as we know it today. The openness allowed more people to move and not emigrate for life, especially in the face of the similar growth and wealth of the countries involved. Mass migration was removed from the equation after World War II and even the recent financial crisis has not led to a dramatic increase in settlement migration nor mobility (Weinar 2019;Sumption and Hu 2011). Still, skilled migrants from both sides of the Atlantic are usually more apt in finding ways to increase their mobility while minimising risks. They benefit disproportionately from arrangements based on economic relations, to be sure, but they also know well how to use them to their advantage. Having no organisation which would support them, they analyse their options offered by the opportunity structure created within the transatlantic space and use their networks to move their social/financial/cultural capital with a lower risk during bi-directional or circular movements over the Atlantic (Weinar 2019;Klekowski von Koppenfels 2014;Bauder et al. 2017). The insights to the privileged position of these migrants in this system can be further gathered when applying intersectional analysis (Kaushik and Walsh 2018). Such analysis, derived from feminist studies, looks at experience of the same category of immigrants through the lens of gender, class, and race/ethnicity. Studies elsewhere have shown the special position of OECD migrants, especially if white, for whom the settlement (and related belonging) is facilitated by privileges of race, class and visa policy (Callister et al. 2006;Boucher 2007). A density and vibrancy of the transatlantic migration system can only amplify this dynamic.
How can we thus make sense of the transatlantic highly skilled migrants? Indeed, they form a quite specific group, clearly different from all other groups of migrants, including highly skilled migrants in other migration systems.

Highly Skilled as Agents in Their Own Lives -A Northerners' Story
The unique opportunity structures in the transatlantic context explain the prevalence of short-term mobility. However, we know little as to what prompts some of the highly skilled migrants to settle or return.
Indeed, as noted by Altbach, according to the National Academy of Science's Survey of Earned Doctorates (SED) in the US, the countries with the most impressive economic and educational expansion seem to be those with the most share of settlers' rates, around the year 2011. The study cites the various dynamics characterising the propensity to stay per region of origin. According to it, three decades ago over a quarter of Chinese doctoral graduates were returning to China immediately after completing their degrees, while in early 2000s this rate dropped to just over 7%. Similar downward trend has been noted for the Indian graduates in the US (13-10%). Yet, return rates vary considerably, ranging from 84% of Thais, 60% of Mexicans and Brazilians, and 39.5% of Africans (Altbach 2013).
As regards European return rates from the US, they have been measured by van Bouwel in a pioneering quantitative study analysing the behaviour of a sample of PhD students in economics (Van Bouwel 2010). Van Bouwel found a high stay rate of 64% for those who find employment upon the completion of their degrees, while 18% returns immediately to their home countries. However, some portion of stayers chose to return later, usually before receiving a tenured position or if they are unable to secure one, increasing thus the overall return rate to 24%. Interestingly enough, close to 11% move to another European country, most often to the UK. This choice is often the preferred one for Italians and Germans in particular.
Another set of data provided by the author focused on the regional disparities between the returnees. Not surprisingly, return rates are lower for the researchers from Eastern Europe: 6% for the first job, and 14% for the second job. The scientific and research environment in these countries can explain the reluctance of the young researchers to come back. Also, the differences in real salaries (purchasing power) do not favour return. Also it seems that the experience in the US does not bring enough return-to-investment benefit on the Eastern European labour markets. In consequence, as the author notes, it seems that these researchers perceive their student migration to the US as a more permanent move, whereas researchers from richer western European countries have a higher tendency of regarding it as temporary. On the other side of the spectrum are the researchers from Scandinavian countries and Southern European countries, where the return rates are higher than average, at 24% and 23% for the return for the first job, respectively. They are even higher for the second job, 32% and 30%, respectively. In the case of Greece, these numbers reached 56% for the second job. These high shares can be explained by the good working conditions in Scandinavian countries, leading the technological breakthroughs in Europe, as well as their social security systems. In the case of Southern Europe, the author explains the high return rates by the cultural and family ties, as well as the high return to investment on the North American experience on the job market (Van Bouwel 2010).
This rather simple quantitative exercise shows already the complexity of factors that can push a migrant to return home, to move onward, or to settle. More qualitative work has helped us delve deeper into the meanders of the migrating decisions.
First element to consider is the propensity to move. What do we know about the mobility of highly skilled migrants across the Atlantic in twenty-first century? The data, cited above, prove that the circularity or temporariness is what defines the migratory dynamics. But qualitative studies show that this mobility is not limited to the transatlantic space for some of the highly skilled migrants. There are in fact several categories of migrants, for whom mobility is way of life and the move over the Pond is one of many they perform. Weinar (2019) presents the results of the qualitative survey of the EU citizens living outside of the EU and observes that for the majority a non-EU destination was their second or third migratory experience. In her sample, many participants were secondary migrants or even serial migrants: nearly 40% had resided for longer than 6 months in one country other than Canada. Forty-six percent of those repeated migrants had engaged exclusively in intra-EU mobility prior to emigrating outside of the European Union, with 33% of this group living in one other EU country, while 12% had lived in more than two. Many participants had also experienced serial mobility outside of the EU. Twenty-seven percent migrated both to EU and non-EU countries, while the same share (27%) migrated only to non-EU countries. A history of extreme multiple migrations was indicated by 8% of respondents, who had lived in five different countries other than their country of citizenship. Among non-EU destinations, the transatlantic space was dominating, with US and Canada accounting for over 50% of all non-EU countries of previous residence (Box 4.3).
It is important to say that in the case of the extreme multiple migrants, none were employees of multinational companies and less than 2% were employed by international organisations. Majority had organised the moves by themselves, usually starting with an international student experience and then moving through a series of international employment opportunities. These highly skilled migrants have been called in the literature professional lifestyle travellers (or self-initiated expatriates/ self-initiated global careerists in management literature) as they use their profession or skills to move between the countries (Ho 2011; Mäkelä and Suutari 2013;

Box 4.3: Middle Class and Middling Migrants
Ball and Nikita define the global middle class as "managers and professionals and their families who move around the globe in the employ of multi-national corporations (MNCs) or as free-lance experts" (Ball and Nikita 2014, p. 85). "Middling migrants" (Conradson and Latham 2005) can be people who migrate on their own as students, skilled workers or spouses and offer their skills on a foreign labour market. In these cases, even if they may not face the discrimination with which lower-skilled workers might be confronted, they do not have the protection of a multinational company's human resource department and may enjoy little actual privilege in the host countries' legal systems. Like many other migrants, they also face the additional constraints of immigration systems or precarious work arrangements (Luthra and Platt 2016). The precariousness is often at the heart of serial mobility, where a migrant's drive to maximise their skills, balanced against fear of losing them, becomes a perpetual trap of changing places and countries.
Eich-Krohm 2012). They are not tied down by a permanent employment contract or a particular company, they are relatively free to move around. More often than not they can be assigned to the "middling migrant" category, as people belonging to the transatlantic middle class and simply using the opportunity structures that lower the risks of international mobility.
That agency of the migrant is the key to understand the mobility sequences. Although all migrants have this agency and control the decision about their move, the transatlantic migration system is the only system in which the risks of the mobility have been substantially lowered and migrants can see their plans through, with only some outcomes left to the factors out of their control. This situation creates a different scale against which we can measure the success of migration. When the risk is lower, the expectations of succeeding are just higher. Most importantly, the success is rarely defined by the sheer ability to settle and stay (Weinar 2019). The expectations are higher as regards the access to the labour market, for example, or the lifestyle. Ability to move and enjoy the benefits mobility can bring, in terms of new skills and experiences, is often seen as a measure of success. At the same time, concepts of "home" or "return" are ambivalent.
Only a few scholars have looked recently at the transatlantic migration and have tried to understand qualitatively the dynamics of mobility and settlement. The scarce literature at our disposal sheds the light on the settlement decision of the twenty-first century transatlantic migrant, in both directions. Weinar (2019) looked specifically at European immigrants coming to North America in recent decades, with a specific interest in the tension between mobility and settlement among the highly skilled while Klekowski von Koppenfels (2014) studied US citizens living in Europe. On both accounts, the authors found several regularities in the migrants' behaviour and migration patterns. Among the US citizens studied by Klekowski von Koppenfels, nearly all of whom were highly skilled in the sense of having tertiary education, joining a partner was the primary proximate reason for migration. In terms of migration aspiration, however, a more recent study shows that working abroad and study abroad both rank ahead of joining a partner (Marrow and Klekowski von Koppenfels 2020, p. 11), suggesting that there is variation between an intended reason for migration and the proximate migration motivator. Marrow and Klekowski von Koppenfels also found that, as education levels declined, US citizens were more likely to indicate migration aspiration in order to join a partner (2018, p. 26), although higher levels of education did not predict higher levels of aspiration to migrate. Having previously lived abroad had a positive affect on individuals' propensity to aspire to migrate, while having social networks with Americans who had lived abroad was significant for predicting migration aspiration (Marrow and Klekowski von Koppenfels 2020, p. 28).
Similarly, for twenty-first century European migrants in Canada, they had usually lived in some other country before deciding on a longer transatlantic move. Most of them actually had been to the country for a shorter visit before migration, they knew the language and had at least some idea about the environment. However, these same people had less propensity to decide for final settlement in Canada. In the Canadian case especially, the interviewed Europeans came as short-term migrants (students or temporary workers) and then changed their status to permanent residency; Klekowski von Koppenfels observed this same tendency among US citizens in Europe, dubbing them "accidental migrants" (2014, p. 43). However, for the Europeans in Canada, the achievement of permanent residence status did not preclude the idea of further mobility or return to Europe, if not necessarily the home country. Still, not only the return to home country was not a priority for over 50% of the interviewees; they were rather thinking about moving to another EU country or another country outside of the EU. These immigrants had proven beyond doubt that they do not shy away from mobility, understand its mechanics, and can follow on their initial plans. Their mobility is not contingent upon limiting economic factors; they do not face drastic differences of economic opportunities upon return. The decision to stay or move is rather related with their life-course. Indeed, the lifecourse analysis seems to be crucial in the case of highly skilled transatlantic migrants; Klekowski von Koppenfels also observed for US citizens in Europe that a return to the US was most likely in the case of a need to care for ageing parents, whilst an onward move was rather linked to exciting and advantageous employment opportunities (2014).
In Weinar's study, the temporary movers are usually in their twenties or thirties. The decision to settle for longer (and this might include getting a citizenship) or to move on/return happens in their 40s. This can be explained by the family-related factors and career-development factors.
Life course events have been recognized as playing a role in affecting both migration decisions and migration trajectories; highly skilled migrants are no different (see, e.g. Ho 2011; Bailey and Mulder 2017). The life-course of a citizen of an industrialised country has changed over the last 100 years. In the twenty-first century, families tend to be more atomic and to expand later in the lifetime of a person, so in their thirties migrants -like others in industrialized countries -only start thinking about having children and settling down. And even having young children is not necessarily a factor enhancing the likelihood of settlement. Moving countries with small children has become much easier in the transatlantic space, with very similar educational and social security systems, so the decision on where the "home" is can be delayed, usually until the schooling age of the children. Indeed, interviewed migrants who were in couples had quite flexible view of the notion of "home". In 80% of cases, they were escaping the strictly diasporic life, often coming back into the fold only for the language schooling of their children. If the migrants came to the new country as a family with children, they focused on the positive impact the move would have on them: new language and cultural skills. These families were curious of other cultures and embraced the idea of living in a global world that offers so much more than just one country. Especially in the US study, many of the presented families were clearly mobile families, who enjoyed the "on the move" lifestyle.
In the transatlantic space, settlement in North America in the case of North American-European couples is not a given. Klekowski von Koppenfels found that over half of her survey respondents in a committed relationship had a partner with European citizenship (2014, p. 101); decisions about where to live depended on a number of factors, including family ties and employment opportunities. While "love migration" (e.g. Mai and King 2009) is certainly an important factor in transatlantic migration, it does not preclude employment -of Klekowski von Koppenfels' US citizen survey respondents in Europe, just under 7% were not employed and not looking for work (2014, p. 80). It is important to note that with partners who both hold "valued" citizenships, and who are both highly-skilled, a wider variety of options in terms of migration and settlement are open. As for professional development, migrating to North America often involves getting new skills or academic credentials to expand the existing career. If the professional situation crystallises by the third year in the North American context, the initial temporary migrants get more clarity about their settlement preferences. Most of the applications for the status change are submitted in the second or third year of the temporary stay (Weinar 2019). Indeed, in the Canadian case, many companies hiring temporary workers from Europe advise them to apply for the permanent residence permit. Interestingly enough, not all do that, even in the face of the offered sponsorship, as many have in their heads progressive career goals that include global mobility beyond Canada (Weinar 2019).
Some scholars describe the decision to settle in a country of destination as the result of interactive multi-level factors, which involve family and career, but also other variables, such as standard of living (Benson and O'Reilly 2009), perceived dynamics of the city they live in (Leslie and Brail 2011), or the level of welfare (Habti 2019). In the case of scientists, some raised the importance of the scientific and technological infrastructure being equally important as the quality of life (Siekierski et al. 2018). Canadian researchers have been especially invested in this type of research, as for two decades now they have been reporting systematic dissatisfaction among the highly skilled migrants with their immigration to Canada (Sapeha 2015). Interestingly enough, the satisfaction with settlement has been associated with integration into the ethnically diverse group, while ethnic enclaves are associated with dissatisfaction. In particular many researchers demonstrated that racial minorities tend to integrate into the Canadian society slower than minorities of European background, what can be associated with the fact that they face less discrimination and thus are more easily welcome into the multi ethnic circles (Sapeha 2015;Reitz 2005;Reitz et al. 2009). In all contexts, highly skilled immigrants from Europe are the ones who are more prone to express their intention to move rather than stay, or have more doubts. Employment satisfaction and the life style are two the most important elements driving the decision to stay.
While there has been a tendency in some literature to identify all migrants from the Global North as lifestyle migrants, we would point out that this group is somewhat less present in the transatlantic space. For North Americans moving to Central America or Mexico, or Northern Europeans moving to southern Spain or France, the classic lifestyle migrant profile can certainly apply --those who leave their countries in search of a better quality of life, often defined in terms of cheaper living costs, milder weather, or a more relaxed lifestyle (Benson and O'Reilly 2009;Benson and Osbaldiston 2014;Cohen et al. 2015;Korpela 2014). While interwar Paris represented a certain lifestyle, with the US dollar then going much further in Paris than it does in 2019, today, lifestyle migration involves other dimensions, many of which are not limited to migrants from the Global North or, indeed, to highly skilled migrants: But the lifestyle choices can involve other dimensions nowadays: access to exciting professional careers or a more technically challenging employment, providing children with additional cultural capital, exposure to new cultures. Lifestyle migration is better thought of as a part of a continuum, rather than as a distinct category; clearly much lifestyle migration is undertaken by highlyskilled migrants, but we caution that by no means are all highly-skilled migrants to be dubbed lifestyle migrants. Indeed, Benson and Osbaldiston caution that "as a label [lifestyle migration] is adopted uncritically and rarely problematized by authors" (Benson and Osbaldiston 2016, p. 409). We note that such lifestyle migration can apply to technically skilled migrants as well as those who are professionals, or highly skilled migrants migrating after their productive years, that is, for retirement. Yet, like many other terms in use in migration research, the term lifestyle migration.

Brain Flows in the Transatlantic Context
As discussed in Chap. 3, the impacts of highly skilled migration on countries of origin and destination can have various facets. In the transatlantic context, issues of brain drain have not been studied in any systematic way in the last 50 years or so. There is a widely shared acceptance of the fact that the "brain trade" (Franzoni et al. 2012) between the two regions has been balanced.
The only area where some studies have emerged is the area of knowledge transfers between origin and destination, as researched by economists (Breschi et al. 2017;Bhagwati and Hanson 2009).
In general, the knowledge transfers, or "brain gain effects," "brain circulation" or "brain flows" have been divided into three, non-mutually exclusive categories: 1. Ethnic-driven' knowledge flows, where the highly skilled migrants use their social networks to promote new ideas among their peers in the country of origin (Meyer 2001). 2. Knowledge transfers facilitated by the mobility within the multinational companies (Blomström and Kokko 1998;Veugelers and Cassiman 2004). 3. Direct impact of the returnees, who use their new skills in their professional life (e.g. students or young professionals) or who engage in new entrepreneurial activities or research activities (e.g. start-ups, research projects) relying on their professional networks at destination (Argote and Ingram 2000).
More specifically, transatlantic economic and social space has been a scene of unique and intense dynamic of two-ways flows of finance, goods, and people. The mutual exchanges of capital and ideas are unquestionable and even taken for granted. It seems to be common sense that all of these three phenomena take place between North America and Europe, but surprisingly, not much research is done to 4.5 Brain Flows in the Transatlantic Context investigate more in depth the ramifications of such strong bonds, even if such a deep understanding could prepare the field for more insightful research into other, emerging, spaces of mobility. The economists working on the questions of brain flows focus predominantly on South-North migrations, and less so on intra-OECD movements.
However, the specificities of the transatlantic mobility makes it very difficult for economists to measure the impacts on the countries of origin and destination. In particular, the lack of consistent datasets on temporary mobility is the major obstacle. As noted by Breschi and colleagues, economists have it easier to study the various impacts of the mobility of Chinese and Indian highly skilled to the US because of the robust data linked to the immigration/emigration status and important real numbers of H1B and J-1 visa recipients from these countries (Breschi et al. 2017). And this is even in the light of the official OECD immigration data, which shows that some European countries are systematically among the top 10 contributors to the stock of highly educated migrants within the OECD, and most notably the UK, Germany and Poland. Indeed, as Breschi et al. noted, the combined stock of these three countries was 60% higher than that of India (top of the ranking) and more than twice that of China in 2011. In their study, the team has thus taken to include several European countries in their rather isolated attempt to build and analyse an extensive dataset of US-based foreign-origin inventors and their knowledge transfers. The category of scientists is not well represented in the official immigration data, i.e. the J-1 category visa data can be misleading, as it covers visitors in various fields and various roles in the broad science and cultural cooperation field, not necessarily inventors. H-1B visa data is even less representative, as it is primarily focusing on temporary highly skilled workers, who however sometimes can be employed in research institutions and develop inventions. In creating their novel dataset, Breschi and colleagues used the EP-INV, a database of uniquely identified inventors listed on patent applications at the European Patent Office (EPO), and combined it with the name analysis based on IBM-GNR, a commercial database. In their analysis, foreign origin inventors include both foreign nationals and US citizens of ethnic origins (both naturalised and US-born). They used an interesting proxy for knowledge transfer, namely forward citations by other scientists related to the patent applications deposed by these inventors. They define the "diaspora effect" as the phenomenon whereby a US-resident inventors of the same ethnic origin have a higher propensity to cite one another's patents, compared with patents by other inventors, other things being equal. They also attempted to see the "brain gain effect", and they defined it as a phenomenon whereby US-resident inventors are disproportionately cited by inventors in their countries of origin. They found diaspora effect almost inexistent in the case of most of the studied European nationalities (Polish, French, and Italian), with some minor effect for German scientists. As regards brain gain effect, the team found that it is quite low, almost inexistent. They concluded that more direct transfers of knowledge, such as co-invention networks and professional networks run by multinational companies have more direct effect. Still, any systematic research in this field has not been developed.
The vast field of research focusing on knowledge transfers in the transatlantic context seem to be created in a total disjunction with the field of migration studies, and does not look at all into the questions of human capital transferability, brain gain or diaspora effects related to migration (Versailles and Mérindol 2006;Allen et al. 2007;Carayannis and Campbell 2006;DeBardeleben and Leblond 2011). Specifically, some authors have attempted analysis of co-inventions in the EU-US context (Carayannis and Laget 2004) but they have not engaged in the analysis of possible role of diaspora networks or short-term mobility, disregarding the actual policy and social environment in which these collaborations could develop and happen. As an unintended consequence, they rather provide a rich picture of short-term motilities of highly skilled migrants across the Atlantic, without really linking previous mobility experience to the intensity of international collaborations.
Another element worth looking at, when talking about impacts on the economic development on both sides of the Atlantic, is the impact on trade. In this case, the overarching studies are rather inexistent. The somewhat general acknowledgement of the impact immigration has on Canada has been offered by the Government of Canada on the contribution of multiculturalism to trade (Government of Canada 2002). Yet, even the studies supporting the negotiations of CETA disregarded the impact of the diasporic or ethnic businesses in the growth of EU-Canada trade. The same can be said about the US case. The research field is atomised and focuses on specific ethnic groups rather than taking an overarching approach to European-North American economic relations through the lens of longer and shorter term mobility of the highly skilled migrants (Anderson 2006).

Conclusions
Transatlantic migration flows have been the cradle of migration studies. The transatlantic migration system is by far the most developed and the busiest in the twentyfirst century. As such it can serve as a laboratory for researchers to test hypotheses and look for trends that will define human mobility tomorrow. At the same time, this migration system has changed substantially over the decades, and diversification of migration flows is the rule, rather than the exception. The mobility of the highly skilled is a case in point -they are the dominant migrant group in the transatlantic space nowadays. They cross the Atlantic in both directions, in different ways: as economic immigrants, as temporary visitors, as service providers, as students and as spouses/partners. They use available opportunity structures and enjoy lower risk mobility for professional or individual development. If they decide to settle, it is often because of their consideration of the specific context: lifestyle, professional opportunities. The classic ideas of wage differentials are no longer a decisive factor shaping the decision to stay. Moreover, even if settled for several years or more, the transatlantic migrants are prone to secondary migrations, return or forward. This extreme mobility reflects the future of all global migrations.
Since the research on transatlantic migrations has not yet been fully developed, we know very little about the actual economic impact the highly skilled might have on the economies at origin and destination. We know a lot about the state of collaboration and knowledge transfers between North America and Europe, but we cannot say with any certainty whether there is a brain drain or brain gain effect in this context. This is in contrast to studies on South-North migrations, where the impact of highly skilled migration is assessed in depth, especially on the countries of origin (see Chap. 3). This persistent gap in research is one of several that should be addressed in further research.
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