Project Summary
This involves the collection, management and analysis of a data on all mass killings in the U.S. since 2006, focusing on characteristics of each incident, offender, victim, and weapon.
Project Description
The mass killing database is a joint venture involving the Associated Press, USA TODAY, and Northeastern University. The database includes all incidents in the U.S. since 2006 in which four or more victims are killed within 24 hours regardless of weapon, location, circumstances and victim-offender relationship. Nearly four dozen variables are collected across four tables—incidents, offenders, victims and weapons, with criminal proceedings tracked through to sentencing. As of December 31, 2024, the database included 612 mass killings (79% involving firearms), claiming the lives of 3,152 victims in total. Compared to the full database, a public version is available that contains nearly all the variables with the primary exception being the names of victims.
Outcome Publications
This dissertation research seeks to broaden our understanding of these rare yet impactful crimes and provide context for policymakers by exploring the shared and unique correlates of homicide and mass murder at multiple levels of analysis, including the individual or offender level, the county or local level, and the state or legislative level. Results indicate that while they share similar characteristics at all three levels, mass murder is a unique crime that cannot be dismissed as homicide with a large victim count. Click here for more details.
In this paper, we rely on the Associated Press/USA Today/Northeastern University Mass Killing Database, which provides the widest coverage of incidents in the U.S. with four or more victim fatalities, regardless of location, situation, or weapon. First, we present trends in incidents and victimization of mass killings from 2006 through 2020, followed by an examination of various incident, offender, and victim characteristics, distinguishing among the major subtypes. Next, we detail a motivational typology of mass murder and identify the common contributing factors. Finally, we consider the potential effects of certain policy responses related to media coverage, mental health services, and gun restrictions on the prevalence of mass killing. Click here for more details.
As defined back in the 1980s, the term “mass shooting” has long been understood to mean the intentional killing of four or more victims with gunfire in a single incident. However, recent efforts to examine this rare and tragic crime have employed alternate definitional criteria. In order to facilitate cross-study comparisons and curb rampant public fear, it is imperative that scholars, politicians, and the media avoid using the same terminology to describe very different phenomena. In this article, we advocate for the traditional definition in view of a variety of theoretical and methodological considerations. Click here for more details.
This article attempts to clarify some of the wide-ranging confusion regarding what exactly is a mass shooting, how often they occur, and whether they have been on the rise over the past several years. After discussion of some methodological issues associated with measuring prevalence, trends exhibited in several reliable data sources on mass shooting are presented. The article concludes with a brief discussion of contagion and whether it is reasonable to expect that the recent spike in mass shootings will persist. Click here for more details.
Accessibly written, yet analytically rich, Extreme Killing: Understanding Serial and Mass Murder, is renowned for its fascinating examination of historical and contemporary serial and mass murder. This book references years of research to bear in this fascinating analysis of serial, multiple, and mass murder and examines and applies the theories of criminal behavior to a multitude of tragic events that involve hate crimes, killings at religious services, music festivals, and school shootings.