Last December, a shootout erupted at a busy intersection in New Orleans. Nearly 50 rounds were fired, yet only one person was hit, a man who suffered a leg injury. In 2013, a similar gunfight took place in New Orleans in which a bullet killed an 11-year-old girl. The two cases can help us understand why murder statistics alone are a bad metric for measuring gun violence trends, says FiveThirtyEight.com. Both featured groups of gunmen firing wildly in the vicinity of innocent bystanders, but only one ended in a tragedy getting extended public attention. Even though 90 percent of New Orleans murders are committed with a gun, looking at total shooting incidents tells more, by focusing attention on all the gun violence in a city. The open data movement is making it possible to evaluate thousands of shooting incidents and develop analytic insights into gun violence's big picture. These conclusions in turn can help evaluate the effectiveness of programs seeking to reduce gun violence.
Whether an individual shooting ends in a fatality is largely random. There can be a number of factors — the distance between shooter and victim, the number of bullets fired, the shooter's age and experience with a firearm, the amount of daylight/moonlight, etc. — that influence whether a shooting incident is fatal or not. Understanding this concept can help explain whether gun deaths in a city are rising or falling because of chance or if a change is due to increasing or decreasing gun violence. It is virtually impossible to figure out shooting incident totals for a city using the FBI’s Uniform Crime Reporting Program. Publicly available UCR statistics count victims rather than incidents, they do not differentiate between murders by firearm and those with other causes, and they count all aggravated assaults the same regardless of what weapon was used. A few cities — particularly New Orleans and Baltimore — organize their publicly available crime data o make tabulation of shooting incidents possible. These cities have historically been two of the country's most violent and are good models for understanding urban gun violence.