Star scientists, innovation and regional and national immigration

"We follow the careers 1981-2004 of 5401 star scientists listed in ISI HighlyCitedSM as most highly cited by their peers. Their number in a US region or a top-25 science and technology (S&T) country significantly increases the probability of firm entry in the S&T field in which they are working. Stars, rather than their disembodied discoveries, are key for high-tech entry. Stars become more concentrated over time, moving disproportionately from areas with few peers in their discipline to many -- except for a countercurrent of some foreign-born American stars returning home. High impact articles and university articles all tend to diffuse. America has 62 percent of the world's stars as residents, primarily because of its research universities which produce them. Migration plays a significant role in some developing countries"--National Bureau of Economic Research web site.