From The Economist
IMMIGRANTS benefit America because they study and work hard. That is the standard argument in favour of immigration, and it is correct. Leaving your homeland is a big deal. By definition, it takes get-up-and-go to get up and go, which is why immigrants are abnormally entrepreneurial. But there is another, less obvious benefit of immigration. Because they maintain links with the places they came from, immigrants help America plug into a vast web of global networks....
In Silicon Valley more than half of Chinese and Indian immigrant scientists and engineers report sharing information about technology or business opportunities with people in their home countries, according to AnnaLee Saxenian of the University of California, Berkeley. Some Americans fret that China and India are using American know-how to out-compete America. But knowledge flows both ways. As people in emerging markets innovate—which they are already doing at a prodigious clip—America will find it ever more useful to have so many citizens who can tap into the latest brainwaves from Mumbai and Shanghai....