By Daniel W. Webster, | Cassandra K. Crifasi, Rebecca G. Williams, | Marisa Doll Booty  | Shani A. L. Buggs

This report is the product of the Reducing Violence, Building Trust: Data to Guide Gun Law Enforcement in Baltimore project. Researchers from the Johns Hopkins Center for Gun Policy and Research (JHCGPR) collected and analyzed data relevant to the enforcement of laws restricting the possession of firearms by prohibited individuals and unlawful carrying of concealed firearms to provide data-driven recommendations for more fair and effective practices. The project was designed to help inform the response to the dual crises in Baltimore—extraordinarily high rates of gun violence, and gun law enforcement practices that, in some cases, have violated the law and more generally weakened community members’ trust in the police. In 2017, Baltimore experienced its highest homicide rate on record during two out of the past three years and had the highest murder rate among cities with a population greater than 500,000 in the U.S.1 Homicides declined in 2018, but in 2019, Baltimore’s per capita homicide rate eclipsed the 2017 record, ending the year with 348 total homicides (58.6 per 100,000 population). Nine out of 10 homicides (291) in the city were committed with firearms. The number of nonfatal shootings in 2019, 771, was also higher than that seen in the past five years.2 Because illegal gun possession is often a precursor to shootings, making arrests for illegal gun possession has long played a prominent role in the Baltimore Police Department’s strategy to combat violent crime. While BPD arrests for drug-related crimes have plummeted by 70% from 2014 to 2019, arrests for weapons violations, principally illegal possession of firearms, have changed relatively little during that time period. Police units focused on illegal gun carrying in hot spots for shootings have helped to reduce shootings, but less focused enforcement practices have not always translated into measurable reductions in violence.3 Past efforts to get illegal guns off the streets and deter illegal gun possession without adequate oversight enabled civil rights violations, facilitated alarming criminal activity by BPD’s Gun Trace Task Force, and increased distrust of the police in many communities. These practices and their aftermath have lasting and harmful implications for public safety and justice. They also motivate current efforts by BDP to facilitate reforms and build trust with community members in compliance with the Consent Decree. Researchers from JHCGPR drew from a variety of sources of data from Baltimore and studies from other cities to summarize key findings concerning proactive gun law enforcement practices—legal issues, impacts of police stops and searches on individuals, impacts on gun violence, community members’ views on the appropriateness of police practices and their desire for greater police accountability, and measures some law enforcement agencies are taking to improve the effectiveness and prevent abuses from proactive gun law enforcement. The report cites prior systematic and expert reviews of relevant research, especially the 2018 report by the National Academies of Sciences, Engineering, and Medicine’s committee on proactive policing.a Several sources of data from Baltimore were used, including: 1) findings from a recent JHCGPR report on the effects of law enforcement and city-led strategies on gun violence (2,3) the United States Department of Justice’s City of Baltimore Consent Decree and reports from the selected Independent Monitor;  3) new data from court records on case dispositions for cases involving charges for illegal firearm possession; and 4) household surveys and focus group interviews with residents living in some of Baltimore’s neighborhoods most impacted by gun violence. The JHCGPR study team sought to identify promising models for effective and fair proactive gun law enforcement through interviews with law enforcement officials in 24 other jurisdictions. This report provides 13 specific research findings relevant to eight recommendations informed by evidence that is intended to guide future proactive gun law enforcement efforts capable of reducing crime and enhancing community confidence and trust.  

Baltimore: Johns Hopkins University, Bloomberg School of Public Health, Center for Gun Violence Solutions, 2020. 65p.

By Nathaniel M. Lesher

With the rising threat of active shooters, armed off-duty and retired law enforcement officers may prove to be an effective tool in American homeland security. Yet, while the number of active shooter and critical incidents in the United States have continued to rise, the number of non-traditional response interventions has remained minimal. Unfortunately, the presence of armed, off-duty law enforcement officers can create other problems, often referred to as blue-on-blue encounters. This thesis examines the questions Can tools such as Hero911 mitigate some of the major risks associated with self-dispatch How can off-duty or plainclothes officers be best incorporated into active shooter response Finally, what processes can make utilization of non-traditional responders safer for all This thesis concludes that over the past 20 years of active shooter responses, first responders have missed an opportunity with respect to the use of non-traditional responders. On- or off-duty non-traditional responders serve as a force multiplier, which widens the pool of available responders. Use of any technology is not without risks, and to avoid more confusion during an active shooter event, training is paramount. Properly used, tools such as Hero911 can reduce the risks involved in non-traditional officer response.

Monterey, CA: Naval Postgraduate School, 2022. 103p.

By Robert VerBruggen

Decades ago, carrying a gun—especially a concealed gun—was a reliable indicator of criminal activity in much of the country. Police officers who noticed a civilian “packing” were justified in assuming that the individual was thereby breaking the law; in short, he was an armed criminal. Under a key 1968 Supreme Court decision, this was reason enough to both stop and frisk the suspect.

Things have changed. Over the past several decades, most states have radically liberalized their gun-carrying laws, first by granting concealed-carry permits on a “shall-issue” basis, which means that anyone who meets certain requirements, such as training and a clean background check, is entitled to a permit. Now, more than 20 states no longer require a permit at all. And in June 2022, the Supreme Court, in New York State Rifle & Pistol Ass’n, Inc. v. Bruen, held that all states must allow law-abiding citizens to carry guns, invalidating New York’s requirement that applicants for a carry license must show a special need to carry, beyond the basic desire for self-defense.

Particularly during a time in which cities across the country have experienced rising gun violence, the court’s decision raises certain issues that need to be resolved. Chief among them: How can police continue to get illegally possessed guns off the street when it is legal—and, indeed, a constitutional right—for many individuals to carry guns on the street?

This report summarizes the legal landscape surrounding stops and frisks. It also investigates—using data from New York City’s stop-and-frisk program—how pedestrian stops of armed individuals tend to play out in practice. The goal here is not to take stances on guns or policing practices. Instead, it is to map out the legal status quo, highlight the tensions among competing priorities, and lay out options that judges and states with different sets of values might consider.

New York: Manhattan Institute, 2023. 17p.

By John J. Donohue, Samuel V. Cai, Matthew V. Bondy, Philip J. Cook

We analyze a sample of 47 major US cities to illuminate the mechanisms that lead Right-to-Carry concealed handgun laws to increase crime. The altered behavior of permit holders, career criminals, and the police combine to generate 29 and 32 percent increases in firearm violent crime and firearm robbery respectively. The increasing firearm violence is facilitated by a massive 35 percent increase in gun theft (p=0.06), with further crime stimulus flowing from diminished police effectiveness, as reflected in a 13 percent decline in violent crime clearance rates (p=0.03). Any crime-inhibiting benefits from increased gun carrying are swamped by the crime-stimulating impacts.

Cambridge Mass. National Bureau Of Economic Research. 2022. 36p.

By United States. Bureau Of Alcohol, Tobacco, Firearms, And Explosives

From the Introduction: "The National Firearms Commerce and Trafficking Assessment (NFCTA) is a comprehensive examination of commerce in firearms in the United States and the diversion of firearms to illegal markets. Produced by a team comprised of ATF [Bureau of Alcohol, Tobacco, Firearms and Explosives] subject-matter experts, academics from a variety of disciplines specializing in research relating to firearms, and other law enforcement professionals, the NFCTA is designed to provide the public, researchers, and policymakers with analysis of data lawfully collected by ATF as part of its regulatory and law enforcement missions to inform the dialogue on firearm law and policy. To ensure comprehensive analysis, the NFCTA is being produced in several volumes. In May 2022, ATF published Volume I, 'Firearms in Commerce'. [...] ATF routinely generates bulletins for law enforcement and industry, and issues public safety advisories for all citizens. This Volume of the NFCTA, however, represents the first comprehensive report incorporating crime gun information from the full range of sources used by ATF in more than twenty years. Advancements in ballistic analytical technology and information processing during this period have enhanced ATF's capacity to support law enforcement efforts to identify, investigate, and prosecute those who use firearms to commit violent offenses and the traffickers who illegally divert those crime guns to criminals. Volume II describes in detail the sources of information that constitute CGI [Crime Gun Intelligence], and how CGI is leveraged to promote effective investigation of firearm-related violence. Finally, the information and analysis in NFCTA Volumes I and II set the foundation for the subject that will be addressed in Volume III, 'Firearms Trafficking.'"

Washington DC. United States. Bureau Of Alcohol, Tobacco, Firearms, And Explosives. 2023. 9p.

BY National Integrated Ballistic Information Network (NIBIN

In 1997, ATF initiated the National Integrated Ballistic Information Network (NIBIN) program. Through this program, ATF provided for the first time comprehensive national automated ballistic imaging services to local, state, territorial, tribal, and federal law enforcement agencies across the country. NIBIN technology captures images of ballistic evidence, including cartridge casings1 recovered in shooting investigations (also referred to as “casings”) and test-fired cartridge casings2 from recovered crime guns (also referred to as “test-fires”), and stores those images in the NIBIN national database that conducts automated analysis for further review by expert technicians. Since 1997, law enforcement agencies have been submitting recovered ballistic evidence to ATF for entry into the NIBIN system, building a national and robust network of ballistic data. As of December 2021, approximately 5.2 million pieces of ballistic evidence have been entered into the system.

Washington D.C. ATF. 2021. 19p.

By The ATF National Tracing Center (NTC) and ATF International Affairs Division (IAD)

ATF and IAD cooperate with international law enforcement partners to disrupt transnational firearms trafficking and reduce violent gun crime in other countries. A central component of this effort is the use of ATF’s eTrace system to provide information on crime guns recovered and submitted for tracing by LEAs in foreign countries. Between 2017 and 2021, ATF received trace requests from an average of 75 countries involving approximately 33,000 crime gun trace requests on an annual basis. ATF continuously works to improve the tracing of crime guns recovered in other countries by completing formal tracing agreements with new international law enforcement partners and training them on the appropriate use of the eTrace system. As of 2021, ATF had eTrace Memorandum of Understandings (MOUs) with LEAs in 47 countries, representing 1,843 eTrace user accounts. To improve accessibility, Spanish language eTrace is available and currently used by law enforcement agencies in Mexico and other Central and South American countries.

The ATF National Tracing Center (NTC) and ATF International Affairs Division (IAD). 2021. 27p.

By Smart, Rosanna; Morral, Andrew R.; Ramchand, Rajeev; Charbonneau, Amanda K.; Williams, Jhacova; Smucker, Sierra; Cherney, Samantha; Xenakis, Lea

3rd. Edition. From the Webpage: "In this report, part of the RAND Corporation's Gun Policy in America initiative, researchers seek objective information about what scientific literature reveals about the likely effects of various gun laws. In the third edition of this report, the authors incorporate more-recent research in their synthesis of the available scientific data regarding the effects of 18 state firearm policies on firearm deaths, violent crime, suicides, the gun industry, defensive gun use, and other outcomes. By highlighting where scientific evidence is accumulating, the authors hope to build consensus around a shared set of facts that have been established through a transparent, nonpartisan, and impartial review process. In so doing, they also illuminate areas in which more and better information could make important contributions to establishing fair and effective gun policies."

RAND Corporation. 2023. 104p.

By Wang-Sheng Lee and Sandy Suardi

The 1996-97 National Firearms Agreement (NFA) in Australia introduced strict gun laws, primarily as a reaction to the mass shooting in Port Arthur, Tasmania in 1996, where 35 people were killed. Despite the fact that several researchers using the same data have examined the impact of the NFA on firearm deaths, a consensus does not appear to have been reached. In this paper, we re-analyze the same data on firearm deaths used in previous research, using tests for unknown structural breaks as a means to identifying impacts of the NFA. The results of these tests suggest that the NFA did not have any large effects on reducing firearm homicide or suicide rates.

Melbourne. University of Melbourne. Melbourne Institute Working Paper Series Working Paper No. 17/08. 2008. 29p.

By Elizabeth P. Shulman, Jordan Beardslee, Adam Fine, Paul J. Frick, Laurence Steinberg & Elizabeth Cauffman

  Objective: To examine whether at-risk male youth experience increases in anxiety, depressive symptoms, and aggression during years when they are exposed to gun violence, adjusting for relevant covariates. Method: Participants were 1,216 male, justice-involved adolescents who were recently arrested for the first time for a moderate offense. They were interviewed 9 times over 5 years. Fixed effects (withinindividual) regression models were used to estimate concurrent associations between exposure to gun violence and three outcomes: depressive symptoms, anxiety symptoms, and aggression (both overall and separately for proactive and reactive aggression). The reverse direction (anxiety, depressive symptoms, and aggression predicting gun violence exposure) was also modeled. Results: After controlling for covariates, exposure to gun violence was significantly associated with increases in reactive aggression and, to a lesser extent, increases in proactive aggression. In addition, gun violence exposure was associated with increased anxiety but not depressive symptoms. We found no support for the reverse direction. Conclusions: At-risk males experienced significant increases in anxiety and aggression (particularly reactive aggression) during years when they are exposed to gun violence, even after accounting for several potential confounding factors. The greater impact on reactive aggression suggests that exposure to gun violence may affect self-regulation and/or social information processing. The analyses shed light on the less-visible damage wrought by gun violence and underscore the importance of mental health screening and treatment for youth who have been exposed to violence – especially gun violence – both to assist individual youths and to disrupt cycles of violence.  

Journal of Clinical Child & Adolescent Psychology, 50:3, 353-366, 2021.,

By Alexander D. McCourt,  Cassandra K. Crifasi, Elizabeth A. Stuart, Jon S. Vernick, Rose M. C.Kagawa, Garen J. Wintemute and Daniel W. Webster

Objectives. To estimate and compare the effects of state background check policies on firearm-related mortality in 4 US states. Methods. Annual data from 1985 to 2017 were used to examine Maryland and Pennsylvania, which implemented point-of-sale comprehensive background check (CBC)laws for handgun purchasers ; Connecticut. which adopted a handgun purchaser licensing law; and Missouri, which repealed a similar law. Using synthetic control methods, we estimated the effects of these laws on homicide and suicide rates stratified by firearm involvement. Results. There was no consistent relationship between CBC laws and mortality rates. There we re-estimated decreases in firearm homicide (27.8%) and firearm suicide (23.2%–40.5%) rates associated with Connecticut’s law. There were estimated increases in firearm homicide (47.3%), non-firearm homicide (18.1%), and firearm suicide (23.5%)rates associated with Missouri’s repeal. Conclusions. Purchaser licensing laws coupled with CBC requirements were consistently associated with lower firearm homicide and suicide rates, but CBC laws alone were not. Public Health Implications. Our results contribute to a body of research showing tha tCBC laws are not associated with reductions in firearm-related deaths unless they are coupled with handgun purchaser licensing laws. 

American  Journal of   Public Health.2020;110:1546–1552. doi:10.2105/AJPH.2020.305822

By Cassandra K. Crifasi,  Alexander D. McCourt and Daniel W. Webster

There is a major flaw in federal firearm laws in the U.S. and in most states’ laws; prohibited purchasers can acquire firearms from unlicensed private sellers without subjecting themselves to background checks and record-keeping requirements. Violent criminals and traffickers exploit this weakness with fatal consequences. A logical and popular approach to fixing this flaw is to extend background check requirements and procedures used for transfers by licensed firearm dealers to transfers from private unlicensed sellers. Research shows that these so-called comprehensive background check (CBC) laws curtail the diversion of guns for criminal use, but have not resulted in significant reductions in firearm-related deaths. Fortunately, there is good evidence showing that when states augment CBC laws with mandatory licensing or permitting of handgun purchasers, lives are saved by lower rates of firearm-involved homicides6, and suicides. Why are comprehensive background checks more effective when augmented by handgun purchaser licensing? The most likely reasons center on the more direct interface between prospective purchasers and law enforcement and more robust systems for verifying the identity of applicants and their criminal records. In most states with handgun purchaser licensing, applicants must apply in person at a law enforcement agency and be fingerprinted. In some cases, applicants must also provide proof of completion of certified safety training. These procedures may deter individuals who might otherwise make impulsive decisions to acquire a gun to harm others or themselves, and in fact studies have found that the presence of licensing laws is associated with lower levels of gun homicides and suicides. Further, the licensing requirements may also deter straw purchases (when an eligible person buys a firearm for a prohibited person or for someone who does not want their name attached to the transfer).  

Baltimore, MD: The Johns Hopkins Center for Gun Violence Solutions, 2019. 8p.

By Michael Siegel

In 2017, there were 14,542 firearm-related homicide deaths in the United States. Despite constituting only 13% of the U.S. population, Black persons made up 59% of these victims. Many states have addressed the problem of firearm-related homicide by enacting stronger firearm laws. While many studies have already been conducted on the effectiveness of various firearm laws in reducing overall population homicide rates, the vast majority of these studies do not distinguish between victims of different races/ethnicity. In failing to do so, these studies assume that state-level firearm laws produce homogeneous effects, even while Black communities continue to bear the undue burden of firearm violence. The purpose of this research was to fill this critical gap by rigorously evaluating the differential impact of state-level firearm laws on homicide rates among White, Black, and Hispanic populations. This project sought to answer two major research questions: (1) Is there heterogeneity in the effect of different state firearm laws on homicide rates by race/ethnicity? (2) To what extent are any differences in the impact of firearm laws by race/ethnicity explained by contextual differences in homicide victimization across urban vs. non-urban settings, as opposed to differences among racial groups per se?

Report to the U.S. National Institute of Justice, 2020. 13p.

By The Philadelphia Interagency Research and Public Safety Collaborative (PIRPSC)

Firearm violence in Philadelphia is a public health crisis. In 2021, Philadelphia suffered a record number of fatal criminal shooting victims (501) and non-fatal criminal shooting victims (1,850). Philadelphia has also experienced extraordinary recent increases in arrests for illegal firearm possession and crime guns recovered, while the Commonwealth has recorded record gun sales in 2020. Despite this crisis in gun violence, shooting arrest rates remain low, conviction rates in illegal gun possession cases have been declining since 2015, and conviction rates in shooting cases declined between 2015 and 2019 and increased modestly in 2020 and 2021.

Firearm violence in Philadelphia is a racial justice crisis. Shootings disproportionately impact Black communities: in Philadelphia over 80% of shooting victims and 79% of arrestees have been Black since 2015. Both victims and arrestees overwhelmingly come from disadvantaged neighborhoods that are majority non-white, have high rates of poverty and unemployment, and less likely to have a high school degree or diploma. Endemic violence in these communities means that the vast majority of those arrested for gun violence have themselves been previously traumatized, often as a witness to previous violent acts; over 80% have previously accessed or been screened for behavioral health services through the City. Because the causes of gun violence are complex and varied, so are the solutions. Addressing the gun violence crisis requires a comprehensive strategy with elements of enforcement, intervention, and prevention to achieve both short-term and long-term reductions in gun crimes. Collaboration among city agencies, including law enforcement and non-law enforcement agencies is critical to successfully implement such a comprehensive strategy. Reviews of evidence-based practices, along with data analysis of local data, have helped us to come to key findings related to gun violence in Philadelphia and have informed recommendations to stem that violence. Readers are encouraged to read both the summary, below, as well as the report in its entirety to understand the context of our recommendations as well as the limitations in both our data and data analyses. 

Philadelphia: Philadelphia Interagency Research and Public Safety Collaborative (PIRPSC)    2022. 196p.  

By Giffords Law Center

The United States accounts for just 4% of the global population but a startling 25% of the world’s prisoners. The mass incarceration crisis that is bloating our nation’s prisons disproportionately affects Black and Brown Americans, tearing apart families and communities—often because of crimes that didn’t involve violence. Data has shown that this “tough on crime” mentality doesn’t actually reduce crime or enhance public safety. While the public is increasingly aware of the harmful impact of failed policies like the war on drugs, a lesser-known yet still significant driver of mass incarceration is the criminal legal system’s response to nonviolent illegal gun possession. Tens of thousands of Americans are arrested and incarcerated each year on nonviolent weapon possession charges. Given that the majority of violent crime in any city is driven by a very small percentage of individuals, we can improve public safety and reduce mass incarceration by rethinking our approach to nonviolent gun possession. This report explores prosecutor-led diversion programs and makes the case for expanding this promising alternative to incarceration.

Washington, DC: Giffords Law Center, 2021. 3 p,

By Rosanna Smart, Andrew R. Morral, Sierra Smucker, Samantha Cherney, Terry L. Schell

In this report, part of the RAND Corporation's Gun Policy in America initiative, researchers seek objective information about what the scientific literature reveals about the likely effects of various gun laws. In this second edition of an earlier work, the authors add five gun policies to the 13 examined in the original analysis and expand the study time frame to incorporate a larger body of research. With those adjustments, the authors synthesize the available scientific data on the effects of 18 policies on firearm deaths, violent crime, the gun industry, defensive gun use, and other outcomes. By highlighting where scientific evidence is accumulating, the authors hope to build consensus around a shared set of facts that have been established through a transparent, nonpartisan, and impartial review process. In so doing, they also illuminate areas where more and better information could make important contributions to establishing fair and effective gun policies.

Monterey CA: RAND, 2020. 412p.

 By Michael Siegel, Kathleen Grene and Amani Dharani 

  Gun violence continues to be a major persistent problem in the United States. According to recent data from the Centers for Disease Control and Prevention, U.S. firearm homicide and suicide rates increased by more than 8% from 2020 to 2021. Approximately 47,000 gun-related deaths occurred in 2021,of which more than 21,000 were homicides. This fall we sought to examine whether there existed a new path on gun safety issues to reduce this high rate of gun violence and death. In Part One, released last month the research identified common ground between gun owners and non-gun owners based on the principle that gun safety policies should keep guns out of the hands of violent criminals. This report “Finding the Common Ground in Gun Safety: Part 2,” built off that common ground by identifying a new package of policies ensuring people at high risk for violence cannot access guns while protecting law-abiding gun owners' Second Amendment rights. This new research and overall package of policies comes at a critical juncture for gun safety issues in the United States. The Supreme Court’s 2022 decision in New York State Rifle & Pistol Association v. Bruen opened the door for courts to potentially strike down “may issue” laws which give law enforcement wide discretion in evaluating permit applications. May issue laws in eight other states are at risk. At the same time recent legislative action at the federal level has shown that gun safety laws are no longer a third rail in American politics and that common ground exists. The “Bipartisan Safer Communities Act” expanded background checks provided funding for red flag laws and strengthened prohibitions on domestic abusers and passed with bipartisan support in both chambers of Congress. However key loopholes in regulation still exist that allow people who are at high risk of violence the ability to access guns. Against this backdrop and informed from the findings from Part One this study identifies gun safety policies that are effective, grounded in shared principles, and respect the rights of law-abiding gun owners. Together with Part One the overall research package identifies a new path forward for gun safety policies that can help save lives and meaningfully reduce gun violence in this country,

97 Percent, 2022. 35p.

By Michael Siegel, Kathleen Grene and Amani Dharani 

Gun violence is a serious problem in the United States. In 2021, there were approximately 47,000 gun-related deaths in the U.S., of which more than 21,000 were firearm homicides. Yet amid this clear and persistent problem, our institutions continue to grapple with how to address gun violence. The Supreme Court in the 2008 decision Heller v. District of Columbia established the constitutional right to keep a handgun in the home for self-defense. More than a decade later, this past June, the Court recognized the right to carry a handgun outside the home for self-defense, opening up new challenges to restrictions on who can carry firearms and where. In the same week, Congress passed the most significant gun safety legislation in nearly three decades, with the Bipartisan Safer Communities Act expanding background checks, providing funding for red flag laws, and strengthening prohibitions on domestic abusers. Against this push and pull, the perception of an intractable divide on gun policy – especially between gun owners and non-gun owners – persists. Yet as our previous research has demonstrated, there is a high level of support among gun owners for a number of gun violence prevention policies.  

97 Percent, 2022. 34p.

By The Giffords Law Center and the Southern Poverty Law Center

“Stand your ground” laws do not deter crime—in fact, they drive up homicides in states where they are enacted. Since 2005, a majority of states have enacted laws that make it easier to get away with murder. These laws distort the usual standard for self-defense by allowing people to use lethal force even if they could have avoided violence by stepping away from a confrontation. Research has shown that these laws lead to more killing and exacerbate systemic racism. Giffords Law Center and the SPLC Action Fund jointly released a new report, “Stand Your Ground” Kills: How These NRA-Backed Laws Promote Racist Violence, analyzing the failure of Stand Your Ground policies.Stand Your Ground does not offer the promised reductions in crime that the NRA and other proponents promised it would; in fact, Stand Your Ground laws have been proven to increase homicide rates and have been called a “low-cost license to kill” by the American Bar Association.

Giffords Law Center and the Southern Poverty Law Center, 2022. 22p.

By Meenakshi Balakrishna and Kenneth C. Wilbur

How well do firearm markets comply with firearm restrictions? The Massachusetts Attorney General issued an Enforcement Notice in 2016 to announce a new interpretation of the key phrase “copies and duplicates” in the state’s assault weapons ban. The Enforcement Notice increased assault rifle sales by 1,349 (+560%) within five days, followed by a reduction of 211 (- 58%) over the next three weeks. Assault rifle sales were 64-66% lower in 2017 than in comparable earlier periods, suggesting that the Enforcement Notice reduced assault weapon sales but also that many banned weapons continued to be sold.

Unpublished paper, University of California, San Diego, 2021. 50p.