Foreign students earning their doctoral degrees in the United States can help revitalize innovation and economic growth. A new study says the U.S. should make it easier for such students to enter and remain in the country.

　　Three economists gathered data on the contributions made by foreign students. The team was led by Keith Maskus, professor of economics at the University of Colorado in Boulder.

　　“My interest was piqued quite a long time ago after September 11th, 2001. One of the reactions to that was that the United States decided for a period of about two or three years to make it much more difficult for students from particular regions of the world to enter the United States and study graduate programs, especially in science and engineering.”

　　He said, at the time, many in Washington and at universities warned that policy would hinder scientific development and innovation.

　　“And I thought, well, that’s very interesting, but do we really know if that’s true?”

　　So Maskus, along with Ahmed Mushfiq Mobarak of Yale and Eric Stuen of the University of Idaho, gathered data – a lot of data.

　　“So what we did is got very detailed individual-level data on quite a large number of students – over 750,00 students, in fact – who had come to get Ph.Ds in the 100 top science and engineering universities in the United States from the late 1970s to the late 1990s. And we had information about where they came from, [including] what their visa status was, what area they wrote their dissertations in and, of course, at which university,” he said.

　　The research indicated that diversity – a mix of American and foreign students -- can make a difference in productivity and efficiency.

　　“It seems to have something to do with the fact that networks and laboratory sciences [are] really a function of how the graduate students and the post- doctoral students and everyone else can specialize in some element of science – and also the fact that their undergraduate training and possibly some graduate training in whatever it is – mathematics or bench science or laboratory science – gives them different approaches to thinking about problems. And when these people can get together and bounce ideas off each other the sort of outcome of that is more dynamic intellectual process. And you get more ideas with having some diversity like that,” he said.

　　To get a U.S. visa, he said, students must demonstrate that either they or their family has enough money to pay for a substantial portion of their education. That’s even if the student’s education is paid for by a scholarship. He says the current philosophy is: you’re welcome to come and study in the U.S., but when you’re done you have to go home.

　　“We think that particular need to demonstrate this kind of income based ability to come to the United States is a little bit short-sighted. Our results show that you really ought to be more open to the highest quality students, regardless of their wealth or income back in their home countries. So that’s one thing. We would urge modification of American visa policy because of that,” said Maskus.

　　Another recommended change concerns permanent residence or green cards.

　　He said, “If you look at policy in other major importing countries, like Western Europe, Canada, Australia – these countries have gone down the road of dramatically increasing the access of what we call green cards -- they call permanent residence – to international students who do get Ph.Ds in science, technology and engineering fields, whether in their universities in those countries or maybe in the United States or in some of these other countries. For example, if you get a Ph.D in the United States, it becomes that much easier to become a permanent resident in Canada.”

　　Maskus and his colleagues say it would help the U.S. compete in the world if doctoral students had an easier time getting green cards. They say, currently, if those students want to remain in the U.S., they must find a local employer, who’ll work on their behalf to get a temporary visa.

　　“That does have the effect, we’re convinced, of pushing too many of these innovative people back outside the borders of the United States. So we argue for increasing the number of those visas and focusing on these students -- or even better -- just offering a very quick and straightforward process to permanent residence,” he said.

　　In their article in the journal Science, the authors say any innovation and economic growth gains would far outweigh any diminished job prospects for American workers.