Income Inequality, Household Income, and Mass Shooting in the United States

Abstract

Mass shootings are becoming a more common occurrence in the United States. Data show that mass shootings increased steadily over the past nearly 50 years. Crucial is that the wide-ranging adverse effects of mass shootings generate negative mental health outcomes on millions of Americans, including fear, anxiety, and ailments related to such afflictions. This study extends previous research that finds a strong positive relationship between income inequality and mass shootings by examining the effect of household income as well as the interaction between inequality and income. To conduct our analyses, we compile a panel dataset with information across 3,144 counties during the years 1990 to 2015. Mass shootings was measured using a broad definition of three or more victim injuries. Income inequality was calculated using the post-tax version of the Gini coefficient. Our results suggest that while inequality and income alone are both predictors of mass shootings, their impacts on mass shootings are stronger when combined via interaction. Specifically, the results indicate areas with the highest number of mass shootings are those that combine both high levels of inequality and high levels of income. Additionally, robustness checks incorporating various measures of mass shootings and alternative regression techniques had analogous results. Our findings suggest that to address the mass shootings epidemic at its core, it is essential to understand how to stem rising income inequality and the unstable environments that we argue are created by such inequality.

Income inequality and mass shootings in the United States

“…In addition, although inconsistently significant across the various models tested, a number of control variables produce significant results and are signed in a counterintuitive direction: population density, minority population, and high school graduation rate. With population density, other studies find that the level of population density is significantly associated with mass shootings [18, 34]. As such, our finding that change in this variable decreases mass shootings may indicate there is a upper threshold at which continued increase in population density no longer increases mass shootings.…”

“…Furthermore, these researchers focus on the implications of gun control legislation, and none of these works analyze the effect of income inequality. Most recently, although some scholars are starting to examine how different levels of income inequality may be connected to mass shootings using counties as the preferred unit [18, 34], there is no research on how the recent growth or change of income inequality is associated with this phenomenon. This study thus adds to the mass shootings literature and public policy debate by shifting the focus away from popular individual-level explanations and towards understudied population-level factors.…”

Won’t You be My Neighbor? Neighborhood Characteristics Associated with Mass Shootings in the USA

“…As we compare to similar studies of mass shootings, our descriptive findings of both economic and racial and ethnic associations with mass shootings were similar to another descriptive report (i.e., Florida & Boone, 2018), lending validity to our results. When comparing our study to a similar multivariate analysis (i.e., Cabrera & Kwon, 2018), we did not find that levels of inequality or poverty rates predict mass shootings at the tract level as they did at the county level. Given the different levels of geography used in the analysis, direct comparisons between our study and this one should be limited.…”

“…One study found that neither gun ownership rates, prevalence of depression, nor poverty had any significant associations with likelihood of a mass shooting at the state level (Lin et al, 2018). At the county level, a longitudinal panel study found that mass shootings are more likely to occur in counties with high levels of both income and income inequality (Cabrera & Kwon, 2018). A descriptive analysis published in a media outlet found that communities with larger black populations were more likely to have a mass shooting, defined as three or more victims (Florida & Boone, 2018).…”

Structural Barriers Associated with the Intersection of Traumatic Stress and Gun Violence: A Case Example of New Orleans

“…Community-level data has shown that urban areas and communities with greater income inequality (having simultaneous higher median income and higher levels of poverty) is associated with more gun violence. This suggests that gun violence is not specifically related to poverty but is likely to occur in areas where there is segregation based on race and economic disadvantage is greater [ 9 ].…”