A Comprehensive Assessment of Deadly Mass Shootings, 1980-2018

Deadly mass shootings have emerged as one of the most prominent social problems in contemporary America. Nevertheless, valid and reliable information on the extent and nature of such incidents does not currently exist, which will inevitably undermine the effectiveness of any “evidence-based” policy efforts aimed at combating such events. Under NIJ’s long-standing program of research related to firearms violence and firearms violence prevention, and the “knowledge building” area within the program, the purpose of the proposed study is to compile a comprehensive database to assess the key individual, situational, and contextual features of all deadly mass shootings in America between 1980 and 2018. This database will be the first of its kind, and it will contain more thorough and detailed information on deadly mass shootings than can be gleaned from any existing data sources. This database will be made publicly available upon completion of the project.

All deadly mass shootings occurring in the U.S. between January 1, 1980, and December 31, 2018 will be identified. These incidents will include all mass shootings where four or more victims were killed (not including the shooter), in one event, in one location. These incidents will be identified in a variety of ways, including through existing reports on mass shootings, media publications, and FBI files. Once a list of all deadly mass shootings is compiled, each event will be coded extensively according to a host of incident, individual, situational, and contextual factors. A clear and detailed coding protocol will be developed to ensure that our methods are replicable.

After all mass shooting incidents are coded, the data will be analyzed using the appropriate descriptive, bivariate, and multivariate analyses that reflect the research objectives and the characteristics of the data. The analyses will determine trends in deadly mass shootings over time, including whether these mass shootings have become more common or more deadly. In addition, we will be able to identify the major individual, situational, and contextual features of all deadly mass shooting incidents, and assess whether these features change over time.

The proposed project will have a significant impact in three respects. First, it is a direct response to a public demand, as well as recent calls made by the U.S. Department of Justice to better understand why mass shootings occur. Second, the proposed project represents a concerted effort to provide methodologically rigorous, accurate, and publicly transparent data on the nature of deadly mass shootings. Finally, the proposed project will have direct implications for public safety. In an era of “evidence-based” policymaking—including developing policies that target gun violence—it is critical that valid and reliable evidence is generated on the problem at hand. Yet to date, such evidence and knowledge does not exist with respect to deadly mass shootings. The proposed research is intended to fill that void and to help inform public policy efforts aimed at reducing deadly mass shootings.


Principal Investigator: Jillian J. Turanovic, Ph.D. 

Co-Principal Investigator: Travis C. Pratt, Ph.D.

Dates: 2019-2020

Funding Agency: National Institute of Justice

Funding Amount: $289,810