Related Experiment Video
Updated: Jun 23, 2025

A Modified Trier Social Stress Test for Vulnerable Mexican American Adolescents
Published on: July 10, 2017
Long gun violence in California versus Texas: How legislation can reduce firearm violence
Jonathan Shipley1, Areg Grigorian1, Lourdes Swentek1
1University of California, Irvine, Department of Surgery, Division of Trauma, Burns and Surgical Critical Care, Orange, CA, USA.
Introduction:
Long guns (LGs) are uniquely implicated in firearm violence and mass shootings. On 1/1/2019 California (CA) raised the minimum age to purchase LGs from 18 to 21. This study aimed to evaluate the incidence of LG violence in CA vs. Texas (TX), a state with rising firearm usage and fewer LG regulations, hypothesizing decreased LG firearm incidents in CA vs increased rates in TX after CA LG legislation.
Methods:
A retrospective analysis of the Gun Violence Archive (2015-2021) was performed. An additional analysis of all firearm incidents within TX and CA was performed. CA and TX census data were used to calculate incidents of LG violence per 10,000,000 people. The primary outcome was the number of LG-related firearm incidents. Median yearly rates of LG violence per 10,000,000 people were compared for pre (2015-2018) vs post (2019-2021) CA LG legislation (Senate Bill 1100 (SB1100).
Results:
Median LG incidents decreased in CA post-SB1100 (4.21 vs 1.52, p < 0.001) by nearly 64 %, whereas any gun firearm violence was similar pre vs post-SB1100 (77.0 vs 74.5 median incidents, p = 0.89). In contrast, median LG incidents increased after SB1100 (4.34 vs 5.17 median incidents, p = 0.011) by nearly 35 % in TX, with any gun incidents increasing by nearly 53 % (83.48 vs 127.46, p < 0.001).
Conclusion:
CA LG firearm incidents decreased following SB 1100 legislation whereas the incidence in TX increased during this same time. Meanwhile, the incidence of any firearm violence remained similar in CA but increased in TX. This suggests the sharp decline in CA LG incidents may be related to SB1100. Accordingly, increasing the age to purchase a LG from 18 to 21 at a federal level may help curtail LG violence nationally.
Related Concept Videos
Bystander Effect
Types of Biopharmaceutical Studies: Controlled and Non-Controlled Approaches
Non-controlled studies, commonly employed for initial exploration, lack a control group, rendering them susceptible to biases and external influences. In contrast,...
Statistical Methods for Analyzing Epidemiological Data
Standards of Care I
Statistical Significance
Comparing the Survival Analysis of Two or More Groups

