Murder rates are falling in a majority of American cities

ON A HOT Wednesday afternoon the office of Chicago CRED, a charity run by Arne Duncan, a former secretary of education, is buzzing. In the car park and inside, dozens of workers dressed in bright vests reading “Peacekeeper” mill around. Each morning they meet at the squat building off 103rd Street in Roseland, a neighbourhood on the far South Side, to share information—who is arguing, what fights or gunshots have already been reported, where gangs might be feuding. The workers then spread out into the neighbourhood in an effort to stop shootings before they happen. By 2.30pm the place is quiet.