Big U.S. cities report another increase in murders in the first half of 2017, likely putting them on track for a third straight year of rising totals after murder rates reached historic lows in 2014, writes Jeff Asher in FiveThirtyEight.com. So far this year’s increase is considerably smaller than it was in each of the past two years; the big-city numbers are consistent with only a modest rise in murders nationwide. Overall, if recent numbers hold, the nation’s murder rate will likely rise but remain low relative to where it was from the late 1960s through the 1990s.
The patterns offer some hints about what the big-city sample suggests about the rest of the year. There tend to be more murders in the second half of the year, when it’s warmer, especially in northern cities. Between 52 and 54 percent of big-city murders occurred in the second half of the year in every year between 2010 and 2015, says the FBI. Recent history suggests that not only does the absolute number of murders increase in the second half of the year, but the rate of increase also accelerates. Big cities tend to exaggerate national murder trends, both up and down, so a large rise in big-city murder usually corresponds with a slightly smaller national increase. If murder rose roughly 8 percent nationally in 2016 and is set to rise a few percentage points in 2017, then the nation’s murder rate in 2017 will be roughly the same as it was in 2008.