Real Numbers: Brain Mobility


The high level of participation of international scientists and engineers in U.S. laboratories and classrooms warrants increased efforts to understand this phenomenon and to ensure that policies regarding the movement and activities of highly trained individuals are sufficiently open and flexible to keep pace with the changing nature of research and technology.

Foreign-born students and scholars contribute at many levels—as technicians, teachers, and researchers and in other occupations in which technical training is desirable. They have also been shown to generate economic gains by adding to the processes of industrial or business innovation. As scientists and engineers become increasingly mobile, their activities will be an element in international relations and even foreign policy.

To maintain its leadership position in science and technology, the United States will have to do more to understand this global network of expertise, to provide a learning and research environment that attracts scholars, to prepare U.S. and foreign-born students alike to function in the evolving global research system, and to implement immigration policies that facilitate the migration of talented individuals so that they can contribute most effectively to global well-being.

Despite the growing presence of international science and engineering graduate students and postdoctoral scholars on U.S. university campuses, the data gathered by different sources on their numbers and activities are difficult to compare and yield only an approximate picture of their career status and contributions. The data presented below (which are taken from the National Academies report Policy Implications of International Graduate Students and Postdoctoral Scholars in the United States) provide a useful introduction to the subject, and they should serve as a catalyst for expanded U.S. efforts to study and welcome the emerging international network of scientists and engineers.

Growing foreign presence at universities

The percentage of international science and engineering (S&E) graduate students in U.S. universities grew from 23.4% in 1982 to 34.5% in 2002. Their presence was particularly strong in some fields. In 2002 international students were 35.4% of all graduate students in the physical sciences and 58.7% of those in engineering. The S&E postdoctoral population was even more international, with almost 60% coming from outside the United States. Information about this group is very limited.

Full-Time S&E Graduate Enrollment by Citizenship

Source: National Science Foundation.

Academic Postdoctoral-Scholar Appointments in S&E

Source: National Science Foundation.

A long period of U.S. dominance

Since the end of World War II, the United States, with 6% of the world’s population, has been producing more than 20% of the world’s S&E PhDs. The strength of the U.S. S&E enterprise is unlikely to falter in the near future, but over the longer term the United States faces challenges in maintaining its leadership.

S&E Doctorate Productivity by Country, 1975–2001

Source: National Science Board.

Signs of a new scientific order

Beginning in 1997, the 15 leading countries of the European Union have published more scientific articles than has the United States. U.S. articles are still 250 the most cited, but European scientists are also closing that gap. Perhaps the most important development is in international collaboration. The percentage of articles with authors from more than one country grew from 8% in 1988 to 18% in 2001. U.S. scientists participated in the majority of these collaborations, and it will be increasingly important for them to maintain these international relationships.

Authorship of Scientific Articles by Country, 1988–2001

Source: National Science Board.

Cite this Article

"Real Numbers: Brain Mobility." Issues in Science and Technology 22, no. 2 (Winter 2006).