By Susan J. Matt, guest op-ed, New York Times, March 21/22, 2012

ACCORDING to a recent Gallup World Poll, 1.1 billion people, or one-quarter of the earth’s adults, want to move temporarily to another country in the hope of finding more profitable work. An additional 630 million people would like to move abroad permanently.

The global desire to leave home arises from poverty and necessity, but it also grows out of a conviction that such mobility is possible. People who embrace this cosmopolitan outlook assume that individuals can and should be at home anywhere in the world, that they need not be tied to any particular place. This outlook was once a strange and threatening product of the Enlightenment but is now accepted as central to a globalized economy.

It leads to opportunity and profits, but it also has high psychological costs [....]