By Paul Michael Reeping

Gun-free zones have the potential to increase or decrease the risk of gun crime and active shootings that occur within their borders. People who assume that gun-free zones increase gun related outcomes believe that the lack of the ability for law-abiding citizens to carry a firearm, and thus an inability to engage in defensive gun use if a threat presented itself, makes gun-free zones a soft target for crime. Those that assume gun-free zones decrease gun related outcomes believe the absence of firearms eliminates the risk of an escalation of violence to gunfire. Up until this point, there has been no quantitative research on the effectiveness of gun-free zones, despite the topic being highly controversial. This dissertation was therefore the first to: create and describe a dataset of active shootings in the United States, and assess the extent to which defensive gun use occurs during these events (Aim 1); conduct a cross-sectional ecological analysis for the in St. Louis, Missouri (2019), both city and county, comparing the proportion of crimes committed with a firearm that occur in gun-free school zones compared to gun-allowing zones immediately surrounding the gun-free zone to quantify the effectiveness of gun-free school zones and (Aim 2); conduct a spatial ecological case-control study in the United States where cases are the locations or establishments of active shootings between 2014 and 2020, to quantify the impact of gun-free zones on active shootings, and assess if active shooters target gun-free zones (Aim 3).. The results of Aim 1 of this study suggested that defensive gun use during active shootings was rare, usually does not stop the attack, and does not decrease the number of casualties compared to active shootings without defensive use. Aim 1 also thoroughly described the novel active shooting dataset. I found in Aim 2 that gun-free school zones had fewer crimes committed with a firearm than corresponding gun-allowing zones in St. Louis, MO in 2019. There were 13.4% fewer crimes involving a firearm in gun-free school zones, with a confidence interval ranging from 23.6% fewer to 1.8% fewer (p-value: 0.025). Aim 3 determined that the conditional odds of an active shooting in an establishment that was gun-free were 0.375 times the odds of an active shooting in a gun-allowing establishment with a confidence interval ranging from 0.193 to 0.728 (p-value<0.01), suggesting that gun-free zones did not attract active shooters, and may even be preventative. In conclusion, gun-free zones did not appear to increase gun related outcomes and may even be protective against active shootings. Efforts across the United States to repeal laws related to gun-free zones, due to the belief that gun-free zones are targeted for violence, are therefore not backed by data. However, these are the first quantitative studies ever conducted on the effectiveness of gun-free zones, so more research is needed to build on the results of this dissertation.

New York: Columbia University, 2022. 133p.

By David C. Pyrooz, James A. Densley, Jillian K. Peterson

Mass shootings, defined as incidents where 4 or more people are shot with a firearm, have become a significant public health concern in the US.

OBJECTIVE - To estimate the prevalence of direct exposure to mass shootings among US adults and identify the socio-demographic groups most affected.

DESIGN, SETTING, AND PARTICIPANTS - A survey was administered in January 2024 to a sample of 10 000 respondents (18 years or older) designed to be representative of US adults using a multistage matched sampling design. In addition to exposure to mass shootings, the survey also collected sociodemographic information, including age, gender, self-reported race and ethnicity, and socioeconomic status.

EXPOSURE - Survey respondents were asked about their lifetime presence at the scene of a mass shooting, any physical injuries sustained (including being shot or trampled or experiencing a related physical injury), and the features of such incidents.

MAIN OUTCOME AND MEASURES - Multivariable logistic regression was used to generate adjusted odds ratios (AORs) of the associations between sociodemographic measures and being present on the scene of and injured in a mass shooting. All analyses undertaken to generate population and relational inferences were weighted to achieve representativeness of US adults.

RESULTS - Of the 10 000 respondents included in the analysis, 51.34% (95% CI, 50.27%-52.40%) were female. In terms of race and ethnicity, 3.04% (95% CI, 2.71%-3.38%) were Asian, 12.46% (95% CI, 11.81%-13.12%) were Black, 16.04% (95% CI, 15.10%-16.98%) were Hispanic, 62.78% (95% CI, 61.73%-63.84%) were White, and 5.67% (95% CI, 5.23%-6.11%) were other race or ethnicity. The findings indicated that 6.95% (95% CI, 6.39%-7.50%) of respondents were present at the scene of a mass shooting, and 2.18% (95% CI, 1.85%-2.50%) sustained physical injuries, such as being shot or trampled, during such incidents. A total of 54.89% of mass shootings to which respondents were exposed occurred in 2015 or more recently, and 76.15% took place in respondents’ local communities. Mass shootings were most likely to occur in neighborhoods. Younger individuals (eg, AOR for Baby Boomer and Silent generations vs Generation Z, 0.12; 95% CI, 0.09-0.18) and males (AOR, 1.55; 95% CI, 1.29-1.85) were more likely to report exposure compared with those from older generations or female individuals, respectively. Black respondents reported higher rates of being present at mass shootings (AOR, 1.87; 95% CI, 1.49-2.34), while Asian respondents reported lower rates (AOR, 0.36; 95% CI, 0.19-0.66), compared with White respondents, but there were no racial and ethnic differences in injuries sustained. CONCLUSIONS AND RELEVANCE The findings from this survey study of US adults underscore the extensive and often overlooked regular exposure to mass shootings in this country. The demographic disparities in exposure highlight the need for targeted interventions and support for the most affected groups, particularly younger generations and males. Understanding these patterns is essential for addressing the broader impacts of gun violence on public health and community well-being.

JAMA Network Open. 2025;8(3):e250283. doi:10.1001/jamanetworkopen.2025, 9p.

By Jillian Peterson, ; Gina Erickson; Kyle Knapp, James Densley

Understanding the motivation of a mass shooter’s intent to do harm can help practitioners and policy makers develop more effective intervention strategies. OBJECTIVE To examine the prevalence of communication of intent to do harm, known as leakage, in a sample of 170 mass public shooters from 1966 to 2019; the characteristics of perpetrators who do and do not leak their plans; and whether leakage is a form of fame-seeking behavior or a cry for help among individuals who are in crisis or suicidal. DESIGN, SETTING, AND PARTICIPANTS This cross-sectional study included perpetrators who killed 4 or more people in a public space from 1996 to 2019 and were included in a comprehensive database of US mass shootings. That database was built from August 2017 to December 2019, and analysis took place from January to May 2021. MAIN OUTCOMES AND MEASURES Leakage was identified and coded using publicly available records. Any communication to a third party of an intent to do harm prior to the shooting was coded as leakage. Logistic regression models were used to examine the risk factors associated with leakage. Models estimating leakage were examined to assess the 2 hypothesized pathways to leakage (the cry-for-help model and the fame-seeking model). RESULTS The 170 participants in this sample included 166 (97.7%) male perpetrators and 3 (2.3%) female perpetrators, with a mean (SD) age of 34 (12) years. Overall, 161 participants had known race and ethnicity: 11 (6.8%) Asian individuals, 35 (21.7%) Black individuals, 14 (8.7%) Latinx individuals, 7 (4.4%) Middle Eastern individuals, 3 (1.9%) Native American individuals, 89 (55.3%) White individuals, and 2 (1.2%) individuals with other race and ethnicity. Overall, 79 mass shooters (46.5%) leaked their plans. Of perpetrators who leaked their plans, 35 (44.3%) leaked specific plans about a mass shooting, and 44 (55.1%) leaked nonspecific plans about generalized violence. The study findings indicate that leakage was associated with receiving counseling (odds ratio, 7.0; 95% CI, 2.0-24.8) and suicidality (odds ratio, 3.7; 95% CI, 1.0-13.6), suggesting that leakage may best be characterized as a cry for help from perpetrators prior to their act. CONCLUSIONS AND RELEVANCE In this study, nearly half of the perpetrators of mass shootings leaked their plans. Leakage was associated with receiving counseling and suicidality. Leakage is a critical moment for mental health intervention to prevent gun violence. Opportunities to report threats of violence need to be increased. Traditional threat assessment models focused on specific threats of violence may miss critical opportunities for intervention. 

JAMA Network Open. 2021, 9p.

By Rocco Pallin, Amanda J. Aubel, Christopher E. Knoepke, Veronica A. Pear, Garen J. Wintemute & Nicole Kravitz-Wirtz

Background

Following the 2018 mass shooting at Marjory Stoneman Douglas High School in Parkland, Florida, there was a dramatic increase in media coverage of extreme risk protection orders (ERPOs) and in state policy proposals for ERPO laws. This study documents the frequency of news coverage of ERPOs throughout 2018 and examines the narratives used by media outlets to describe this risk-based firearm policy.

Methods

Using a mixed-method descriptive design, we examine the frequency of national news media coverage of ERPO legislation in 2018, before and after the Parkland shooting, and analyze the content of news articles related to a sample of states that considered ERPO legislation after the shooting.

Results

We find a sharp increase in the frequency of articles related to ERPOs following the Parkland shooting and smaller increases in coverage surrounding ERPO policy proposals and other public mass shootings that year. Nearly three-quarters of articles in our content analysis mentioned the Parkland shooting. The news media often mentioned or quoted politicians compared to other stakeholders, infrequently specified uses for ERPOs (e.g., prevention of mass violence, suicide, or other violence), and rarely included evidence on effectiveness of such policies. More than one-quarter of articles mentioned a mass shooting perpetrator by name, and one-third of articles used the term “gun control.”

Conclusions

This study describes the emerging public discourse, as informed by media messaging and framing, on ERPOs as states continue to debate and implement these risk-based firearm violence prevention policies.

BMC Public Health 21, 1986 (2021), 13p.

By Jason R. Silva

This study examines the reality and news media coverage of all mass shootings in the United States from 1966 to 2016. It employs agenda-setting and framing theoretical frameworks to determine the social construction of mass shootings via the mass media. The project uses open-source data to create a comprehensive list of mass shooting incidents. It then identifies all published New York Times articles on each incident. The study summarizes both the reality of the social problem (i.e. incidents) and the news mediated reality (i.e. New York Times). Next, this dissertation conducts a media distortion analysis to determine the perpetrator, motivation, and incident characteristics influencing media selection, prominence, and framing. The purpose is to illustrate the media’s social construction of mass shootings that in turn shapes public perceptions, political discourse, and public policies. The study concludes by highlighting the findings and implications for scholars, practitioners, policy-makers, media outlets, and the general public.

New York: City University of New York (CUNY), 2019. 164p

by Kelly Drane

In many communities across the country, gun violence has been an unrelenting drumbeat. In a single deadly day, gun violence claimed the lives of a 31-year-old father in Port Allen, Louisiana; a 43-year-old in Philadelphia, Pennsylvania, who was known as a stylish dresser with a great sense of humor; an 11-year-old in Columbia, Missouri, who loved to dance and play with her cousins; and a 17-year-old in Columbus, Ohio, who was a gifted boxer.

Each day, hundreds of lives like these are lost or irrevocably changed as this crisis rages on.

But in the last two years, the tempo of this beat has gotten faster. Gun violence has skyrocketed in cities and towns across the country, leaving more devastation and more trauma in its wake.

More than 45,000 Americans were killed in acts of gun violence in 2020—a 15% increase over the previous year. This increase was primarily driven by an unprecedented 35% rise in gun homicides. In fact, more people were lost to gun violence in 2020 than any other year on record, and although final data is not yet available, the gun death total in 2021 is likely to surpass these records.

This drumbeat is ever-present, but one to which too many have become numb. For too long, this epidemic has gone unchecked, and even as it has spiraled out of control, too many leaders are choosing to do nothing. This moment demands attention, and we must do more to mitigate these increases and protect communities in crisis.

This report provides data describing how gun violence has skyrocketed in 2020 and 2021, showing that this historic rise in gun violence has primarily served to intensify this crisis in communities that already suffered the greatest burden. Additionally, this report describes and considers the factors that most likely contributed to these increases, based on available evidence, and makes suggestions for how policymakers can best respond to this unprecedented challenge.

San Francisco: Giffords Law Center to Prevent Gun Violence., 2022, 3p.