The extent of an international "brain drain" to the US is revealed in a new study by Warwick University, to be presented at an international conference this month.
The study tracks the careers of hundreds of elite physicists, biologists and economists and finds significant evidence of talent being funnelled into the US after graduation.
It also uncovers a particularly striking early exodus in economics, according to the authors.
"The US is acting as a giant funnel for brilliance, sucking in talented people from all over the world to a really disproportionate extent," Andrew Oswald, an economics professor at Warwick and one of the report's authors, said.
The report shows that 75 per cent of assistant economics professors working in the top ten US universities gained their undergraduate degrees in other countries, including the UK.
"These findings are consistent with concerns expressed about the growing dominance of US economics departments in academic research," Professor Oswald said.
The report also shows that, of a sample of 158 of the world's top physicists, nearly 44 per cent are no longer working in the country where they were born. Switzerland and the US provide the strongest lure, most likely fuelled by higher salaries and readily available funding, the report says.
It also looked at elite bioscientists working in the US, showing that 44 per cent were born outside the country - with Japan, followed by the UK and Canada, being the major "donor" counties.
Professor Oswald said the results gave cause for concern: "As a small country in Western Europe, I think we should worry about the brain drain ... Universities need to think hard about the best way to respond and one approach may be to specialise in what you are good at."
The report, Elite Scientists and the Global Brain Drain , is to be presented at the second International Conference on World-Class Universities being held in Shanghai from the end of this month.