Saturday, September 12, 2015

Murder Worse in 2/3 of Our Largest Cities

Nate Silver's statistical website FiveThirtyEight has an article looking at the homicide rate in the nation's 60 largest cities. First the bad news:
The results confirm that there has been an increase in homicides this year in big U.S. cities of about 16 percent.
They accumulated (with difficulty) data on homicides for 59 of the 60 largest cities, data for Anaheim were not available. In 25 of the 59 cities for which data were available:
Homicides were up by 20 percent or more from a year ago.
Homicides rose by less than 20% in 14 additional cities, and were down in the remaining 20 cities. Concluding on a positive note, they observe:
While a 16 percent increase in U.S. major-city homicides is statistically significant, it comes after decades of declines — the murder rate fell by more than half nationally from its peak in 1980 to 2012.
Honestly, much of the article is a long whine about how good, real-time homicide data isn't easily available. Unless statistical shtick is your thing, skip the last half of the article.

Unfortunately, 2015 bids fair to be an inflection point on the homicide trend line. That is, the point at which the trend line shifts to head off in a new, more deadly direction. This distinct possibility is not any part of 538's preferred story line.