Stop the Arbitrary Benchmark for a Mass Shooting

There is surprisingly little agreement on what a mass shooting is, or how many there have been.

News headlines across the country labeled the massacre in Boulder, CO as the nth ‘mass shooting’ to happen this year. While these headlines are commonplace, there is surprisingly little agreement on what a mass shooting is, or how many there have been.

The Department of Homeland Security, FBI, Department of Justice, media outlets, and academics all have their own definitions of a mass shooting. It’s usually not a mass shooting if it’s gang-related, drug-related, part of another crime (like 5 people shot during a bank robbery), a serial killer, domestic violence, or inside a private residence.

The government doesn’t count 25 people shot at a block party in Chicago as a “mass shooting” if police suspect the shooter, or victims, were gang members. Labeling the attack as gang violence versus a mass shooting doesn’t change the outcome for bystanders caught in the crossfire.

Rick McKee, staff cartoonist at The Augusta Chronicle

Depending on who is counting, a mass shooting can be either:

• 4 or more victims killed

• more than 4 victims killed

• 4 victims either killed or injured

• shooter may or may not count as one of the fatalities or injuries

Why would you count the shooter? It doesn’t seem ethical to combine the perpetrator with the victims, right? Back to the block party, if one attacker started firing shots into a crowd and 3 other people began firing back, are those three people shooters or victims?

Change that fictional scenario to an active shooter in a Walmart. There happens to be a customer with a concealed weapon who fires back at the shooter. Unfortunately, the armed customer misses the attacker and shoots another bystander. Are the armed citizen and the person he unintentionally shot in the shooter or victim count? Does the bystander shot by the other victim count toward the ‘mass shooting’ total?

This situation might seem crazy except that in the real world, a school security guard (who wasn’t allowed to be armed) shot 2 students while firing at a police officer who he thought was a school shooter during the STEM School attack in Colorado in 2019. Both students who were shot by the security guard are counted as victims even though the armed students attacking the school were on the opposite side of the campus. Numbers get messy fast.

The problem we have in America is someone with a gun killing a group of people in a public place. Sometimes many people are killed, other times there are few victims. There can be a careful plan involving an arsenal of weapons that results in hundreds of victims like Las Vegas. Alternately, only a few shots are fired before the gun jams, or a bystander tackles the shooter. Mass public violence is about the intent to kill as many people as possible, just like terrorism is intent to send a political message through violence. If a bomb in a marketplace kills 2 people instead of 200, is it not terrorism because there weren’t enough victims?

Why is 4 the magic number that makes something different and turns an everyday American shooting into a ‘mass shooting’ that should be reported on, counted, and studied? Basing mass shooting on a death toll ignores all the other variables that dramatically influence how many people die. These factors include:

• heroic victims and bystanders: a shooting can be stopped before it becomes a mass shooting by victims who risk their own lives to subdue the shooter. The 2019 STEM School shooting in Colorado was not a “mass shooting” because a heroic student, Kendrick Castillo, died when he rushed the shooter to shield his classmates. Without his selfless act of bravery, many students would have lost their lives.

• type of firearm: a shooter with a semi-auto rifle with a high capacity magazine that holds 15–100 rounds is going to kill more people than with a break-action shotgun that holds 2 shells. If the shooter has weapons that are similar to those used by law enforcement and militaries around the world, they will kill more victims than someone would with a conventional hunting firearm (black powder rifle or shotgun). Firearms expressly designed to kill people will kill more people.

• ammo: type of ammo changes the speed and amount of energy the bullet carries. Shotgun shells have loads with various sizes of pellets that cause different amounts of damage. One can blow apart a duck with a shell designed for a deer, but not kill a deer with a shell designed for a duck. A .22 round from a compact revolver does less damage than a .308 round from a rifle traveling at 2,500 ft/second through multiple victims, walls, and barriers. It is also legal to buy, manufacture, and sell ammo designed to pierce armor. A shooter who uses high velocity rounds that are “jacketed” to allow for more penetration will kill more victims. For example, the shooter at the Aurora, CO theater attack used a high velocity rifle to kill his initial victims. When the rifle jammed, he switched to a shotgun that had “bird shot”, which was fortunately less fatal, than heavy slugs, buck shot, or the rifle rounds from his discarded weapon.

• distance from shooter to victim: all projectiles lose velocity as they travel. Accuracy of a shooter decreases as distance increases. If the shooter is closer to the victims, these shots are more likely to be fatal. For example, in a 1998 school shooting in Arkansas, two teens pulled the fire alarm and shot from the treeline (100 yards away) at students evacuating the school. Despite an ambush by two shooters with an array of weapons, 5 students were killed and 10 were injured, because of the long distance between the shooters and victims. During the shooting in Parkland, FL in 2018, 17 victims were killed, and 17 more injured, when the single shooter fired at close range in the school hallways. Less distance equals more victims and more fatalities.

• skill level: the amount of training and practice the shooter has with a weapon impacts how effectively they can aim, fire, and reload it. Back to the Aurora, CO theater shooting, his gun jammed and the shooter didn’t know how to clear it. He dropped the semi-auto rifle and switched to a shotgun that was loaded with less lethal shells designed for bird hunting. The shooter’s low skill level and limited knowledge of ammo resulted in fewer fatalities. A skilled shooter would have easily cleared the jam and continued to fire the rifle into the crowded theater.

• number of shots: if a shooting occurs in a crowded public area, firing more shots has a higher chance of killing or injuring victims. During the Las Vegas music festival shooting that killed 59 and injured 500, more than 1000 rounds were fired during a 10-minute period.

• number of weapons: along with the number of shots fired, a shooter with multiple weapons has the potential to kill and injure more victims. The Las Vegas shooter had 20 different rifles set up in his hotel room. Multiple rifles are likely to have a higher number of fatalities than a shooter with one handgun. The Aurora theater shooting could have ended when the rifle jammed, but the shooter had multiple backup weapons to switch to.

• targeting of victims: if a shooter is targeting specific victims — annoying coworkers in an office or the popular kids at a school — those victims may be killed, while bystanders are wounded when they are caught in the crossfire. A targeted victim may be shot multiple times at close range, while random victims may be only struck once from a distance.

• density of a crowd: shots fired into a crowd may strike multiple people, or inversely be blocked by the victims closest to the shooter, depending on the location, density, and type of weapon and ammo used. 10 shots fired from a .22 pistol in a crowded night club might only strike 5 victims. 10 shots fired in the same club, from a .223 semi-auto rifle with high velocity jacketed rounds, could hit 30 victims.

• duration of incident: a gunshot requires rapid treatment to control the bleeding. If a shooting is over in a few seconds (like a drive-by at a block party), EMS may be able to treat and transport victims within minutes. A shooting that becomes a barricade could last for hours before EMS can reach the victims. Longer incidents are more likely to have high fatality rates if the injured victims cannot receive prompt medical treatment.

• emergency response time: a shooting in a rural area with 6 police officers and one volunteer fire department is going to have a slower response time than a shooting in a major metro area with dozens of different law enforcement agencies and robust emergency medical services. A shooting victim who gets rapid treatment in an urban area might die in a rural one.

• distance to hospital: just like response time for police and EMS, a shooting victim needs to get to a hospital quickly. If a shooting occurs in close proximity to a Level 1 Trauma Center, the victim has a different rate of survival than the same victim in an area where a trauma center is a 90-minute drive.

• capacity of hospital: if there are more victims with severe injuries than the local hospitals have capacity to treat, the victims will be prioritized to maximize resources and save as many as possible. If 30 people are shot in an area with multiple large hospitals, those 30 people have a better chance of receiving treatment than if the same incident happened in a rural area with one small hospital.

None of these factors relate to the intent of the shooter to kill and injure people. They are all variables that change the number of people injured or killed. A skilled shooter with multiple weapons in a rural area might kill 40 people. If that same incident happened in an urban area, the death toll could be 10 because there are more police to respond and faster medical treatment. Does that make one incident significant while the other isn’t? If a shooter with 1,000 rounds of ammo carefully planned an attack, but his gun jammed after shooting the first victim, is that incident less of a “mass shooting” than someone who fired 10 shots from a handgun during an argument at a BBQ and hits 5 bystanders?

The point is that the number of fatalities is arbitrary. The magic number 4 doesn’t make a shooting more or less important. We should focus on the circumstances and intent of the situation, rather than the number of victims. Saying “this is the nth mass shooting this year” is an empty statement without substance or rigor that dilutes our attempt to understand a complex problem with dozens of variables. Let’s end the counting and focus on the issues behind all of these senseless tragedies.

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David Riedman is the creator of the K-12 School Shooting Database and a national expert on school shootings. Listen to my recent interviews on Freakonomics Radio, New England Journal of Medicine, and Iowa Public Radio the day after the Perry High shooting.