From “Reasonable” to “Necessary”: Evaluating California’s AB 392 and Police Use of Deadly Force

In 2019, California’s AB 392 changed the police deadly force standard from “reasonable” to “necessary in defense of human life.” Earlier constraints on officer discretion reduced police shootings, but whether AB 392 did the same is unclear. Using incident-level records of every officer firearm discharge in California (URSUS) and a national database of police shootings (SPOTLITE), we ask whether deadly force fell relative to other states, whether any effect was concentrated in “elective” shootings, and whether officer injuries rose. A synthetic control finds no reliable cross-state effect (p = .294), and no count outcome within California holds up across all robustness checks. One result does: shootings that struck someone became more likely to be fatal (56% to 62%), especially when civilians were armed with knives or edged weapons. Officer injuries show no clear rise, though the estimate is imprecise. The law left “necessary” undefined, which may explain its modest effects.