Gun violence is usually measured in deaths and injuries, but the ShotSpotter system measures shots fired:
Last year, there were 165,531 separate gunshots recorded in 62 different urban municipalities nationwide, including places such as San Francisco, Washington, D.C., St. Louis and Canton, according to ShotSpotter, the company behind a technology that listens for gunfire’s acoustic signature and reports it to authorities.
Even that eye-popping number captures only a fraction of the bullets fired each year. It does not include data from rural areas or the nation’s two largest cities — Los Angeles does not use ShotSpotter and New York City was excluded from the 2015 tally because it did not start until mid-year.
The ShotSpotter system also covers just a sliver of each city that it is in, usually higher-crime neighborhoods. ShotSpotter’s total coverage was 173 square miles last year. And the devices tend to not hear gunshots fired indoors.
Still, the data begins to provide a fuller picture of the nation’s rampant gunfire.
Last year, those 165,531 gunshots were divided among 54,699 different incidents — an average of 150 gunfire incidents every day.
The busiest month for gunfire was May.
The busiest day was Dec. 25, Christmas.
And if you want to avoid getting shot, it’s best to lie low from 2 a.m. to 3 a.m. on Saturdays. That was the busiest hour of the week for gunfire. The slowest hour was 8 a.m. to 9 a.m. on Mondays.
Doleac, at the University of Virginia, and Purdue professor Jillian Carr used ShotSpotter data for Washington to determine how the city’s juvenile curfew affected gun violence.
The ShotSpotter devices were rolled out first in Anacostia in 2006, then Southeast and Northeast neighborhoods and finally north of downtown. The researchers examined gunshots detected from 2006 to 2013.
What they found was surprising: The city’s curfew actually increased the number of gunfire incidents by 150% in the hour immediately after it went into effect.
The researchers focused on the one-hour period when the city’s curfew changed each year, going from midnight every night in July and August to 11 p.m. on weeknights the rest of the year.
During that hour switch-over, they found, gunfire spiked. The researchers theorized that this was because law-abiding juveniles were most likely to follow the curfew. They got off the streets. That resulted in fewer innocent witnesses or bystanders in public, potentially leading to more lawlessness and gunfire.
In another study, Doleac and Carr found that ShotSpotter data showed evidence of “severe underreporting” of gun violence when compared to the traditional metrics of homicides or 911 calls.
In Washington, just 1 in 8 gunfire incidents led to a 911 call for “shots fired” in the covered areas.
“It’s clear most people don’t bother to call 911,” Doleac said.
In Washington, there was one reported homicide for every 181 gunfire incidents.
In Oakland, Calif., the other city that researchers studied, it was one homicide for every 62 gunshot incidents.
They noted with interest that it appears Oakland’s gunfire was at least twice as deadly as Washington’s gunfire. Although the researchers couldn’t come up with the reasons behind this difference (Were Washington’s gunmen poor shots? Did victims in Oakland get to the hospital more slowly?), the difference points to how measuring gun violence with homicides is problematic.