Inequality may be the result of global economic forces, but it matters in a local sense. A city where the rich are very rich, and the poor very poor, is likely to face many difficulties. It may struggle to maintain mixed-income school environments that produce better outcomes for low-income kids. It may have too narrow a tax base from which to sustainably raise the revenues necessary for essential city services.

http://chicagoist.com/2014/03/09/chicago_ranks_eighth_in_income_ineq.php?ncid=tweetlnkushpmg00000067