The mitigating effect of low firearm background check requirements on firearm homicides in border states.

Background: Firearm-related violence is a significant public health issue in the US. Research has found an increase in guns used in crimes sourced from low gun law states into high gun law states. The purpose of this study is to evaluate the effect of distance from states without universal background checks (UBC), background checks at shows (BCS), or permit to purchase (PTP) laws on firearm homicide rates in states with them.

Methods: States were identified based on their enactment of laws that are designed to prevent the private sale of firearms to criminals. Demographic data for each county were obtained for the years 2014 through 2017. The border distance from a county in a state with the evaluated gun laws to the nearest border state without the gun laws was obtained using Google Maps. Multiple regression analyses were performed to test the relationship between border distance and firearm homicide rates.

Results: The regression model evaluating all formats found the border distance was negatively associated with firearm homicides (p=.009). The parameter estimate indicated as border distance increased, the firearm homicide rate decreased. When counties with UBC or PTP on all guns were evaluated separately from all formats model, the statistical significance was lost (p=.62). In counties where all handgun sales either require a background check or a PTP is required, the distance was also not statistically significant (p=.11).

Conclusions: This study provides evidence that there may be a mitigating effect on the reduction of firearm homicides in states that require background checks or PTP on private sales when there is a state in close proximity that did not have these laws. Limited counties at certain distances may have contributed to the insignificant findings in other models.