Violent crime is down since the turn of the millennium here in Chicago, as it is in New York and LA, bucking the national trend. Some of this may be attributable to innovative policing strategies, but the Economist suggests a curious influence–the aging population of these three cities. When the cost of living goes up, young people move out. Young people not only commit more crimes, they’re also more likely to be targets of crime. But while the spiraling cost of living in America’s big cities might be making the city safer, it obviously doesn’t bode well, since young people don’t just take your money, they take your jobs, too. (h/t Kottke)