Firearm violence following the implementation of California’s gun violence restraining order law

by Pear VA, Wintemute GJ, Jewell NP, Ahern J.
April 05, 2022

Quick Summary

CA's gun violence restraining order law was not significantly associated with a reduction in firearm violence of any kind during its first 4 years of implementation, 2016 to 2019.

About the Research

FINDINGS IN BRIEF

In the study period, there were 355 GVROs in San Diego county, and a median (IQR) total of 8 (3-20) GVROs per donor county.
The mean difference between the observed rate in San Diego County and the estimated rate in the synthetic San Diego County, 2016-2019, was −0.74 firearm assaults per 100 000 (−13% difference) and 0.13 firearm self-harm injuries per 100 000 (3% difference).
Results from in-space placebo tests suggested that these differences cannot be distinguished from variation due to chance (pseudo-P values from a 1-sided test: P for assault = .35, P for self-harm = .67).

IMPLICATIONS AND CONCLUSIONS

To our knowledge, this study was the first to analyze the association between GVRO implementation and firearm violence in California and the first to evaluate the association between risk-based firearm removal laws and firearm assault in any state. These results suggest that gun violence restraining order implementation did not reduce population-level rates of firearm violence in San Diego County, but future studies should investigate whether there were individual-level benefits to those directly affected.

METHODS

This serial cross-sectional study including data from 28 counties used the synthetic control method to evaluate differences in firearm violence between San Diego County and its synthetic control following implementation of the California law from 2016 to 2019. San Diego County was used as the treated unit because it issued substantially more GVROs than any other county in California during the study period. A total of 27 California counties that issued no or very few gun violence restraining orders from 2016 to 2019 and that had stable rates of firearm violence between 2005 and 2015 were included in the control pool. Data were analyzed from February 2021 to July 2021.

Citation

Pear VA, Wintemute GJ, Jewell NP, Ahern J. Firearm violence following the implementation of California’s gun violence restraining order law. JAMA Network Open. 2022 Apr 5;5(4):e224216.