Association of Firearm Purchaser Licensing Laws with Intimate Partner Homicide.

The share of intimate partner homicides (IPHs) committed with firearms has increased steadily since 2013. To date, limited research has examined whether firearm purchaser licensing laws, which mandate a more robust screening process for firearm purchases, impact rates of firearm IPH. We obtained weighted and imputed counts of IPH from a modified version of the Federal Bureau of Investigation's Supplementary Homicide Reports for the 1990-2019 study period. We used augmented synthetic controls to assess purchaser licensing adoption in Connecticut and Maryland, repeal in Missouri, and partial repeal in Michigan. We stratified outcomes by victim race and firearm involvement to examine differential impacts of licensing policy changes. In Missouri, repealing licensing requirements was associated with significant increases in firearm IPH (27.6%) and overall IPH (21.0%). The harmful effects of Missouri's repeal were evident among Black victims of firearm IPH, whereas no significant changes were observed in firearm IPH rates among white victims. The partial repeal in Michigan was not associated with significant changes in firearm IPH. The impact of purchaser licensing adoption on IPH in Connecticut and Maryland was less clear as there were no significant changes in firearm IPH rates. Our findings suggest that removing a safeguard to prevent illegal firearm purchases may contribute to increases in IPH that differentially impact Black individuals. Future research should leverage recent purchaser licensing policy changes to further explore how these requirements may influence IPH trends.