Gun ownership has a great deal to do with mass shooting events:
From: Lemieux F. Effect of gun culture and firearm laws on gun violence and mass shootings in the United States: A multi-level quantitative analysis. International Journal of Criminal Justice Sciences. 2014 Aug 7;9(1).
A significant finding is that mass shootings and gun ownership rates are highly correlated (r=0.75; p<0.01) and that this association remains high even when the number of incidents from the United States is withdrawn from the analysis (r=0.39; p<0.05). In other words, the higher the gun ownership rate, the more a given country is susceptible to experience mass shooting incidents; further, this relation is not impacted by an outlier effect induced by a large number of incidents in the United States.
From: Lankford A. Public mass shooters and firearms: A cross-national study of 171 countries. Violence and victims. 2016 Jan 1;31(2):187-99.
The results showed a statistically significant association between national firearm ownership rates and the number of public mass shooters per country (b 5 3.39, p 5 .002).
[A] major finding is that firearm ownership rates appeared to be a statistically significant predictor of the distribution of public mass shooters worldwide. Many of the nations in this study that ranked highest in firearm ownership rates also ranked highly in public mass shooters per capita.
From: Reeping PM, Cerdá M, Kalesan B, Wiebe DJ, Galea S, Branas CC. State gun laws, gun ownership, and mass shootings in the US: cross sectional time series. BMJ. 2019 Mar 6;364:l542. doi: 10.1136/bmj.l542. PMID: 30842105; PMCID: PMC6402045.
Results: A 10% increase in state gun ownership was associated with a significant 35.1% (12.7% to 62.7%, P=0.001) higher rate of mass shootings.
Conclusions: States with more permissive gun laws and greater gun ownership had higher rates of mass shootings, and a growing divide appears to be emerging between restrictive and permissive states.
From: Daraklis, M., Pol, M., Johnson, L.
et al. A Statistical Analysis of the Impact of Gun Ownership on Mass Shootings in the USA Between 2013 and 2022.
J Urban Health 101, 571–583 (2024).
https://doi.org/10.1007/s11524-024-00881-9
Gun ownership was found to be significantly associated with the rate of mass shooting fatalities. Specifically, our model indicated that for every 1-SD increase— that is, for every 12.5% increase—in gun ownership, the rate of mass shooting fatalities increased by 34% (p value < 0.001).