As immigration has grown in volume, so has its complexity. Today, people do not simply move once and settle. They increasingly keep on moving, twice or more, not just between their country of origin and destination, but to multiple destinations. This onward migration, or multiple migration, is supposedly on the increase, according to the burgeoning research on the subject.
In theory, it makes sense. Once one migrates, subsequent movements become easier (just like learning new languages). Networks established through initial migration reduce the risk of re-migrating, while newly acquired experience provides more options to venture out further. Financial and legal resources gained through initial migration also help. This may particularly be true when initial migration is directed from poor countries to richer ones. Acquiring citizenship in the initial rich country opens up possibilities to move on to other (rich) countries, as does familiarity with labor market practices in the “First World.” Since more and more destinations adopt stricter immigration policies favoring the skilled and educated, this also facilitates the multiple movements of the resourceful. Resource-constrained migrants, on the other hand, may also find it necessary to navigate the systems of multiple countries to reach their preferred destinations.
In practice, however, it is challenging to estimate, and quantify the volume of onward migration. This is because most countries, primarily concerned about who and how many should come in, do not collect emigration data on who leaves and for where. There is also a challenge in the very definition of onward migration (how long one should stay in each country to qualify as an onward migrant, for instance?). And it is next to impossible to determine when migration actually stops. Today’s “destination” may actually become tomorrow’s “origin” country.
In my earlier studies using the US Census and other data, I have nevertheless estimated that 10-13% of migrants arrived in the US via a third country, other than a country of their birth. The government of New Zealand recently reported that 25% of its skilled migrants re-migrate out of the country within five years of taking up residence (Krassoi-Peach 2013). Emigration of immigrants from the UK has been a “growing phenomenon” (Finch et al. 2009: 6). Canada is also concerned about “immigrant brain drain,” as it loses many skilled and educated migrants to the US (Boudarbat and Connolly 2013).
Why do some people keep on moving, while others migrate just once, return home, or do not move at all? This is a lingering question and a research agenda of my own, ever since I stumbled upon immigrants moving, or aspiring to move, on from Japan to the US. Why do they move on from one rich country to another, and what do they gain, and fail to gain, from each country? Interviewing multiple migrants in Japan and the US, I have found that an important factor lies in the process of “capital” accumulation in the initial migration. That is, how their skills are utilized and valued, and what kind of knowledge and resources are acquired in migrating to Japan.
The portability of capital may be particularly crucial. Migrants who acquire globally portable skills in Japan, rather than Japan-specific skills, are more likely to move on to another country, such as the US. A talented Chinese businessman aspired to move to the US after having acquired multi-lingual proficiency and global business know-how in Tokyo’s financial district. A Korean engineering student, enrolled in a newly established “global English program” at a prominent Japanese university, told me during an interview that he aspired to move on to the US before “assimilating too much to the Japanese system” which he regarded as parochial and a hindrance to further movements. A series of globalization policies, implemented to attract and retain global talent in Japan, therefore, may actually result in reinforcing the country’s role as a stepping-stone to other (Western English-speaking) countries.
I am a “multiple migrant” myself. Born in Japan, I received much of my higher education and academic career in the US before moving on to the UK. I have also lived or studied in Peru and Spain for over six months each. And if I shorten the length of stay required in each country, I may add Mexico and Germany to my list. Why do I keep moving? It is partly because I have acquired the taste for novelty, and partly because it has become habitual, as if it were my “job” to migrate. But most of all, I moved on, because I had the option, and the privilege, not only to move to, but also to exit and to return to a previous country.
In an age of growing human mobility, immigration research, as well as policy-making, continues to assume that there is one country of origin and one destination. Yet, it is important to build a multi-country framework, as migrants today increasingly assess, and compare, multiple countries in deciding whether to migrate, to where, and when. And we must not forget that while some people keep on moving, others remain immobile, out of their own volition or not, who may not even consider migration as an option at all in their everyday lives.
http://www.migrationpolicy.org/article/secondary-migration-who-re-migrates-and-why-these-migrants-matter; Takenaka, A. 2013. “Re-migration of Immigrants to the United States: Who Re-Migrates and Why?” Pp. 223-241 in LeMay M. (ed.), Immigration and Superpower Status: U.S. Immigration History and Issues, Praeger Publishers. 2013
 Krassoi-Peach, E. 2013. How Permanent is Permanent Migration: Identifying the Determinants of Remigration for Skilled Migrants in New Zealand. Wellington, NZ: Ministry of Business, Innovation and Employment of the Government of New Zealand.
 Finch, T., M. Latorre, N. Pollard, and J.Rutter. 2009. Shall We Stay Or Shall We Go? Re-migration trends among Britain’s immigrants. London: Institute for Public Policy Research.
 Brahim Boudarbat, Marie Connolly. 2013. “Brain Drain: Why Do Some Post-Secondary Graduates Choose to Work in the United States?” Project Report. CIARO. Accessed on December 15, 2014 from www.cirano.qc.ca/pdf/publication/2013RP-12.pdf