Does gun ownership lead to mass shootings in the U.S.

What is the relationship between mass shootings and gun ownership? In this study, we explore whether gun ownership measured by the number of guns owned in states is associated with mass shooting incidents in states. Using the aggregate data compiled from various sources such as Crime Research, we conduct multiple regression analyses to examine whether more mass shooting incidents will be observed where there is higher gun ownership after controlling for various compositional differences across states. The preliminary zero-order relationship shows that the percentage of mass shootings positively correlates with gun ownership. In multiple regression analysis, we will further examine whether this correlation holds after controlling for potential confounders such as the prevalence of illegal gun ownership, types of gun laws, and various socio-economic and demographic differences across states. Because our study uses aggregate level data, we are unable to completely rule out the possibility of ecological fallacy. Despite this limitation, however, the results from our study will help us understand what drives the positive correlation between gun ownership and mass shootings