When the term “mass shooting” appears in headlines, most people picture high-profile tragedies in schools, workplaces, or other public locations. These events dominate news coverage, shape public debate, and drive prevention planning. Yet there is no universally agreed-upon definition of a “mass shooting,” and as members of the Regional Gun Violence Research Consortium wrote in July, differing definitions not only can shift the reported number of fatalities for mass shootings collectively, but also can profoundly impact how mass shootings are conceptualized and prevention strategies are identified.

Since many definitions and most media coverage focus on public settings of mass shootings, incidents that occur inside private homes often go unnoticed. Below, I outline the findings of a new study colleagues and I conducted on this issue and identify key insights and recommendations. When using a broader and widely applied definition (four or more people killed, excluding the perpetrator, regardless of location or circumstance), a stark reality emerged in our study: the home is the deadliest setting for mass shootings in America.

New Research On Mass Shootings In the Home

In the recent study I coauthored with Pragya Bhuwania and Jody Heymann, we used this broader definition in considering settings of mass shooting events. Using Gun Violence Archive’s mass shooting database, we restricted events to those in which four or more people were killed, excluding the perpetrator, and conducted a media analysis to determine whether each event was related to domestic violence (i.e., whether one or more of the victims was a current or former intimate partner or family member of the perpetrator). That left us with a dataset of 252 mass shooting events that occurred between 2014 and 2023, resulting in 1,464 deaths. Analyzing that dataset, we found that half (50 percent) of all those mass shooting fatalities occurred in private homes.

The toll mass shooting fatalities in home settings is especially devastating with respect to children. Among victims under age 10, nearly 90 percent were killed in home-based mass shootings. For youth ages 10 to 17, 62 percent of mass shooting fatalities occurred in the home. While school shootings understandably draw wide attention, we found that home-based shootings less visibly claim far more young lives: for children under 10, over 22 times the share of fatalities occurred at home than in schools, and for youth ages 10 to 17, the proportion killed at home was more than double the proportion killed in schools.

Adult deaths from mass shootings also occur at home more than any other location: 44 percent were found to have occurred in private residences, while 10 percent occurred in businesses or workplaces, the second-most common location, and where adults typically spend the largest share of time outside the home. Adult women are further disproportionately represented in home-based mass shooting fatalities, with half of all such adult female deaths taking place in home-based events compared to 40 percent of adult male fatalities.

Prior research has shown that there is an alarming connection between domestic violence and mass shootings, but has not examined where domestic violence-related events most frequently occur. It would be reasonable to infer that mass shooting events occurring at home might be related to domestic violence, and, indeed, our research findings highlight that domestic violence may help explain part of this pattern. We found that nearly half (47 percent) of all mass shooting deaths between 2014 and 2023 occurred in incidents linked to domestic violence, and 70 percent of fatalities in home-based shootings happened in such contexts. But domestic violence is not the full story: 30 percent of home-based mass shooting deaths occurred in events unrelated to domestic violence, underscoring that domestic violence alone does not explain home-based mass shootings. We found that many of these events were thought by law enforcement to be related to drug activity, neighbor or roommate disputes, or robberies.

Moving the Conversation about Home-Based Mass Shootings Forward

For years, media and policymakers have concentrated on mass shootings in schools, workplaces, and other public spaces. These are, of course, urgent areas for intervention. But the disproportionate focus on public mass shootings has left home-based tragedies less visible in prevention agendas. If we are serious about reducing mass shooting deaths, we must expand how we define, track, and respond to them.

Better Data

Discrepancies in definition and inclusion criteria among existing mass shooting databases limit our understanding of the public health effects of mass shootings. Stronger and more consistent national data collection on mass shootings that includes events that occur in all circumstances and locations would help expand our collective knowledge of mass shootings and guide more targeted, evidence-based policy and public health prevention efforts. Policymakers and public health practitioners should consider including home-based incidents in official counts and prevention planning to help better align public understanding of mass shootings with reality and help direct further resources to addressing the areas of greatest risk.

While our study focused on events in which four or more fatalities occurred and specifically examined age and gender breakdowns of fatalities, it is also important to consider injuries when tracking mass shootings. About twice as many nonfatal firearm injuries occur as fatalities per year, and nonfatal injuries contribute substantially to the mental, physical, and economic toll of gun violence in the United States. Using broader definitions of “mass shooting” based on number of injuries (rather than fatalities) in future research can help us better understand the broader impact of incidents of mass gun violence that occur in the home, and consider high profile events with profound effect on communities—such as the recent shooting at a Minneapolis Catholic School in which two children were killed and over 20 others were injured—in data-driven prevention planning.

Targeted Policy

In addition to improving data collection, policymakers should recognize the clear role of domestic violence in mass shootings and consider strengthening and improving enforcement of laws that authorize removing firearms from known abusers. Expanding survivor supports—including safety planning, housing, and legal aid—can also help those affected by domestic violence find safety. Beyond domestic violence, we found that in 34 percent of the mass shootings included in our sample, the perpetrator died by suicide or was killed by law enforcement. This highlights the need for other strategies to address home-based risks, like promoting safe firearm storage to gun owners, expanding crisis intervention and mental health and substance use treatment services, and strengthening policy tools like Extreme Risk Protection Orders (ERPOs) that temporarily reduce firearm access during periods of crisis.

Public Awareness

While mass shootings are widely covered in the media, many in the United States may not know that half of mass shooting fatalities occur in the home or that home-based shootings are particularly fatal for children. Other important facts about gun violence, such as that almost 60 percent of gun deaths are by suicide each year or that firearm injury is a leading cause of death for children and teens, may also not be widely known by the public or policymakers. Researchers and policymakers can collaborate to ensure that key information that can help individuals and families keep themselves safe from gun violence is disseminated effectively through media and other public awareness initiatives. The home is where people expect to feel safest. Yet when it comes to mass shootings, it is also where many—especially women and children—are most at risk. Until we acknowledge this reality, our prevention strategies will remain incomplete. Recognizing the hidden toll of home-based mass shootings is the first step toward saving lives too often overlooked.

ABOUT THE AUTHOR(S)

Wilson Hammett is an affiliate scholar with the Regional Gun Violence Research Consortium and a postdoctoral scholar in the Fielding School of Public Health at the University of California, Los Angeles.