The objective of this study is to examine the intercontinental movement of highly cited researchers (HCRs) in the field of engineering. We use the data on HCRs available from the Thomson Scientific database (http://www.highlycited.com/), covering a 20-year period (1981–1999), combined with information collected from the internet and the researchers themselves, to examine the movement in engineering around the world of the HCRs from birth to their present affiliation. We establish that there is a steady movement of engineers from Europe and the rest of the world to the U.S.
There is a steady movement of engineers from Europe and the rest of the world to the U.S.
Movement is Common
Intercontinental movement of scientists is a very common practice. Among scientists, 41.4% have completed at least one of their degrees, or are working, in a continent different from the one where they were born.
Table I provides information on the numbers of highly cited (HC) engineers according to their present affiliation. U.S. institutions dominate the list, in terms of HCRs in engineering (68.2%).
Frequencies and percentages of HCRs in engineering according to their current affiliation
Next we examined the geographical breakdown of the numbers of HCRs, taking into consideration the country of their birth, the country where the researchers’ first degrees were obtained, and the country where Ph.D. degrees were obtained.
We first looked at the countries where the HCRs obtained their Ph.D. degrees (Table II).
Frequencies and percentages of HCRs in engineering according to the country where their Ph.D. studies were completed
U.S. universities still have a clear advantage over European, Asian, and universities in the rest of the world, but the advantage is slightly decreasing when the comparison is made with respect to current affiliation of the HCRs.
In engineering, one in three HCRs who completed their doctorates in Europe are now affiliated with a U.S. institution, a pattern that was also observed in the field of mathematics (see ). The opposite is very rare. Asia has a much higher retention rate than Europe, as has Canada (5) and Australia (3).
We also found that there is no movement at all between Europe and Asia. It seems as though many scientists from Asia and Europe who had an exceptional career that allowed them to become HCRs, either did their Ph.D. in Asia and Europe and then moved to the U.S., or they obtained a Ph.D. degree in the U.S., and then returned to their country of origin (this happened mainly with Canada and Australia).
This finding, if supported by further evidence, may suggest that Europe and Asia need to strengthen their scientific collaboration in this important field of scientific endeavor.
Looking at the countries where the highly cited engineers earned their first degree reveals more interesting facts (Table III).
Frequencies and percentages of HCRs in engineering according to the country where the first degree was completed
Out of 239 HCRs, 41.8% (100) had completed their B.Sc. degree studies in the U.S., 23.4% earned their B.Sc. degrees in Europe, and 28.9% had B.Sc. degrees from institutions in countries outside the U.S. and Europe. In engineering, the phenomenon of movement of HCRs between B.Sc. and Ph.D. studies is not as strong as in the field of mathematics, where researchers having completed their B.Sc. studies in the EU exceeded those in the U.S. (33.2% and 32.7%, respectively).
From a total of 155 HCRs affiliated with U.S. institutions (where information on both their affiliation and their B.Sc. studies was available), 27 (17.4%) and 21 (13.5%), respectively, acquired their first degree in Asia and in the EU. This corresponds to the 62.8% of the HC engineers who completed their B.Sc. degree in Asia, and to the 37.5% who completed their B.Sc. in the EU. Hence, Asia is by far the continent losing more of its engineering potential through a brain drain towards the U.S. From the nine HC Chinese engineers who obtained a B.Sc. degree in China, only one is currently working in China.
Birthplaces of HCRs
Table IV looks at the birthplaces of the HCRs. Once again, by cross-tabulations between affiliation and country of birth, we found that Asian HC engineers contribute the most to the transfer towards U.S. institutions (66%), followed by EU HC engineers with 46.2%. The EU tends to retain its HC scientists more efficiently when compared with Asia.
Frequencies and percentages of HCRs according to their country of birth
We find also that the movement from Europe to the U.S. (20.1%) heavily outnumbers the opposite movement (5.9%). Only about half of the researchers working in the U.S. are native-born (51%). For the rest of the world the vast majority of researchers are native-born citizens (see Fig. 1).
We also conducted a more detailed investigation, looking at the specific current institutional affiliations of HC engineers. We found that out of the top twenty institutions in engineering, ranked from the point of view of HCRs, sixteen are in the U.S., while only two are in Europe (CERN and EPFL), and two are in Canada (University of Waterloo and University of Toronto). No Asian Institution appears in the top 20 list, despite their strong tradition in engineering.
Also, no U.K. university appears in the top 20 engineering list with respect to HCRs. This finding supports the concerns voiced by industry in the U.K. about that country’s engineering programs.
There are 6 Institutions in California in the top 20 list, five of which belong to the University of California system. This finding needs further examination in order to see if there is a connection to the existence of the Silicon Valley in California. Stanford and UC Berkeley, in addition to a high number of HCRs in engineering, show a very high overall number of HCRs. This confirms the diversity of these two institutions in nurturing top researchers across scientific disciplines. For the other institutions appearing in the list, it is apparent that their main emphasis is in engineering.
Observing the percentages of native and non-native HCRs in each one of the top institutions, we found that for the majority of the U.S. institutions, their HCRs originate from countries outside the United States. For instance, at Stanford, six out of eleven HCRs come from countries outside the U.S., and at M.I.T., four out of nine. There are also more extreme cases. For instance at the University of California Los Angeles, all HCRs (four) were born outside the U.S.
Highly Cited U.S. Engineers were Nurtured Elsewhere
The findings in this article indicate that a significant proportion of highly cited engineers working in the U.S. were scientifically “nurtured” elsewhere.
While further research is needed in order to continue advancing the understanding of the movement of scientists, this study can be seen as a first step towards a better understanding of the mechanisms behind the deemed U.S. global superiority in science and in higher education.
J. Panaretos and C.C. Malesios are with the Department of Statistics, Athens University of Economics and Business, 76 Patision St, 10434 Athens, Greece. Email: firstname.lastname@example.org.