Date of Degree


Document Type


Degree Name



Criminal Justice


Jeremy Porter

Committee Members

Joshua Freilich

Amy Adamczyk

Subject Categories

Criminology and Criminal Justice | Demography, Population, and Ecology


Mass public shootings; diffusion; social integration; Event history analysis


In the last 40 years, social scientists have provided important insights into the different characteristics of mass public shootings: their prevalence, types, patterns, and individual risk factors. However, we still lack a fundamental understanding of the processes that shape its incidence and spatial distribution. Our failure to tap into these dynamics is rooted in our inability to escape the dominant paradigm in which this phenomenon has been examined. Literature on mass murders, and most recently on mass public shootings, has been trapped by an analytical framework that cares only for individual risk factors. This paradigm is myopic because it assumes that only the proximate causes (i.e., factors and events closest to the attack) shape the prevalence and distribution of such attacks.

The goal of this study is to step away from this paradigm and recast these shootings as a social phenomenon, shaped by social forces. This investigation is couched on three major Sociological/Criminological theoretical perspectives: social integration, social disorganization, and imitation/diffusion theories. Under social integration/social disorganization theory, I posit that certain ecological characteristics (primarily low social cohesion) make certain populations more at risk or vulnerable to these types of massacres. Similarly, I argue that an imitation or diffusion process, driven primarily by media exposure, also shapes the incidence and spatial distribution of these attacks.

A Continuous-time Event History Model (or Hazard/Survival Model) is used to test the influence of social integration and imitation/diffusion forces on the prevalence of mass public shootings in the contiguous United States for the 1970-2014 time period. The results paint a mixed, but rather interesting picture. From the theoretical perspective findings are mixed. Imitation/diffusion and social disorganization theory were not supported by the results. Durkheim’s social integration theory was the most successful, but also partially supported.

Despite these mixed findings, the results provide unexpected and interesting insights into the social causes of mass public shootings. The findings show that (contrary to expectations) the occurrence of a mass public shooting was found to depress the odds of future attacks. We also learned that mass public shootings tend occur in states that are more rural, with greater levels of marriage stability, and social-economic status. These are quite unique findings, as these relationships tend to be reversed for regular homicide. The results suggest that mass public shootings behave more like suicide, than regular homicide. This study is the first to provide insights into the sociological roots of mass public shootings. As such, the results provide a springboard for the future literature.