The New York Times, June 10, 2009 by Jim Lewis
http://www.nytimes.com/2009/06/14/magazine/14prisons-t.html?_r=1
As Jonathan Simon, a law professor at Berkeley, pointed out to me, convicts tend to come from cities; guards do not. Culture clashes inevitably arise. Skilled labor — doctors, psychologists and the like — is harder to find in rural areas, and so are the volunteers who work in the many rehabilitation programs. The families of working-class and poor convicts often can’t afford to travel a few hundred miles to visit their relatives. As a result, prisoners have a harder time maintaining ties with the lives they left behind.