Rockefeller Institute, Brent R. Klein: “Protecting children from gun violence in K-12 schools means facing two realities: the roots of violent intent and the destructive capacity of firearms. In a recent study published in Criminology, my colleagues (Cory Schnell, Steve Chermak, and Josh Freilich) and I revisited a decades-old question: do firearms or motivations to kill drive mortality during school shooting assaults? The answer was striking. Lethal intent mattered—but so did the weapon. Of the incidents we studied, when a shooter used a higher-caliber gun, such as a .45 caliber versus a .22 caliber handgun, the chances of someone dying in the event increased even after controlling for the shooter’s background and, importantly, why they acted. In short, caliber counts. Encouragingly, there are concrete policy steps that can be considered and implemented to make it count less. Against this backdrop, our study took a different head-to-head approach that was grounded in specific data. Using original data from The American School Shooting Study (TASSS), we were able to track both what school shooters did—concrete behaviors signaling specific intent to cause serious harm—and the firearms they carried, including size, caliber, and design. This dual focus allowed us to see just how human motivation and weaponry interacted to shape the odds of survival during injurious school shooting incidents.
Most school shooters in our study acted with lethal intent: nearly three-quarters (73 percent) opened fire with the goal of killing or seriously injuring someone. Fewer brandished firearms to defend themselves (21 percent), intimidate a person (7 percent), or for other reasons. Many of these decisions were calculated rather than impulsive (71 percent), and more than half occurred after someone provoked the shooter (57 percent). The largest group—about 44 percent of all cases—involved shooters who made preplanned and unprovoked decisions to kill, the clearest marker of murderous intent. School shootings perpetrated by these individuals were 18 percent more likely to result in death. …the weapon’s lethality amplified the outcome regardless of the shooter’s mindset. But intent was only part of the story. The firearms themselves mattered just as much, if not more. Using more powerful guns, measured by features like caliber (the diameter of the bullet) and muzzle velocity (speed at which a bullet leaves the firearm’s barrel), increased the probability of death by about 22 percent, even after accounting for intent and other relevant variables. In other words, the weapon’s lethality amplified the outcome regardless of the shooter’s mindset. Access to firearms also shaped these events. Most shooters did not purchase their own weapons. Instead, 80 percent of shooters obtained the firearm they used through family, friends, or informal markets, suggesting that the power of the weapon often reflected availability, not careful selection by the shooter. Put simply, who pulls the trigger is critically important, but so is what they carry in their hands…”
