Chicago's 2012 murder total was 532. NYC's total number for 2012 was 417. Even in absolute numbers this is significantly lower than Chicago! Amazing. The comparable homicide rates for NYC and Chicago are 5 and 20 per 100,000.
Homicides in New York City declined 19 percent from 2011 (just to remember: in 1990 2,245 people were killed in NYC). To get such a substantial drop on such a low (by US standards) homicide number needs some explaining. Chicago saw a 23 percent increase from 2011.
Had the New York numbers gone up and the Chicago numbers gone down, you'd hear sage mumblings from chin stroking academics about regression to the mean (which, of course, assumes there is a mean (average) homicide rate toward which to regress... but I digress). I'll tell you what the answer isn't: people in New York just loved each other more; while clearly hate was on the rise in Chicago.