Research team captures an elusive shadow: gun ownership by state

Policymakers face an extraordinary challenge: how to reduce the damage caused by firearms while preserving the right of citizens to carry weapons and protect themselves. This is especially true because the Supreme Court has overturned New York State rules limiting who can carry a concealed weapon.

While meaningful legislation requires an understanding of how access to firearms is associated with different consequences of harm, this knowledge also requires accurate, highly substantiated data on firearm possession, data currently unavailable due to a lack of a comprehensive national firearms ownership register.

Newly published research by data scientist and firearms proliferation researcher Maurizio Porfiri, institute professor at NYU Tandon School of Engineering, and co-authors Roni Barak Ventura, a postdoctoral researcher at Porfiri’s Dynamical Systems Lab, and Manuel Ruiz Marin of Universidad Politécnica de Cartagena, Spain , describe a spatial-temporal model to predict trends in state-level firearms prevalence by combining data from two available proxies: background checks per capita and suicides committed with a firearm in a given state. The study “A spatio-temporal model of firearms ownership in the United States,” in the journal Patternsdescribes how, by calibrating their results with annual survey data, the team determined that the two proxies could be considered simultaneously to obtain accurate information about firearms possession.

Porfiri has spent the past few years researching arms acquisition trends and how they relate to and are influenced by a number of factors, from media coverage of mass shootings under the influence of the incumbent president.

“There is very limited knowledge about when and where weapons are obtained in the country, and even less is known about future ownership trends,” said Porfiri, professor of mechanical and aerospace, biomedical and civil and urban engineering and incoming director of the Center. for Urban Science and Progress (CUSP) at NYU Tandon. “Previous studies have largely relied on the use of a single, selected proxy to draw some conclusion about weapons prevalence, usually within simple correlation schemes. Our results show that there is a need to combine sales and violence proxies to provide precise draw conclusions about firearms prevalence.” He added that most research aggregates the number of measures within states and does not take into account interstate interference or spillovers.

Their research shows how their model can be used to better understand the relationships between media attention, mass shootings and firearms possession, and uncover causal links that are masked when the proxies are used individually.

For example, while the researchers found that media coverage of firearms control is causally related to firearms possession, they found that their model that generates a strong firearms ownership profile for a state was a strong predictor of mass shootings in that state.

“The potential link between mass shootings and the purchase of firearms is a unique contribution of our model,” said Ruiz Marin. “Such a link can only be detected by looking at the exact gun counts in the country.”

“We combined publicly available data variables into one measure of ownership. Because it has a spatial component, we were also able to track the flow of weapons from one state to another based on political and cultural similarities,” said Barak-Ventura, adding that the spatial component of the work is new. “Previous studies looked at a correlation between two variables, such as increasing background checks and an increase in gun violence.”

Barak-Ventura said the team is now using their model to examine which policies are effective in reducing the number of firearms deaths in a state and surrounding regions, and how the relationship between gun ownership and violent impact is disrupted by various legislation.