This article details recent efforts in California to identify and target high-risk firearm owners to help prevent firearm violence, including mass shootings.
The article first describes gun violence restraining orders, also known as extreme risk protection orders, which provide a judicial mechanism for firearm recovery and a time-limited prohibition on firearm purchases. Next, it discusses California's Armed and Prohibited Persons (APPS) database and enforcement system. APPS is used to identify newly prohibited persons among legal firearm owners and to help law enforcement recover those firearms. Finally, the article highlights early research in which machine learning for rare-event detection is employed to forecast individual risk, using California's decades worth of firearm transaction records and other readily available administrative data. The approaches described range in scale, scope, and strategy, but all three enable targeted intervention at times of heightened risk. In so doing, they offer the potential to provide outsized benefits to efforts to prevent mass violence. (publisher abstract modified)