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.

By Christopher S. Koper

Controlling gun crime continues to be a difficult challenge for policymakers and practitioners in the United States. With an estimated 258 million guns in private hands and millions more produced each year, there are many sources and means through which offenders can obtain firearms despite legal restrictions on gun purchasing and ownership by convicted felons, juveniles, and other high-risk groups. In order to better understand the workings of illicit gun markets—and particularly the rapid diversion of guns from the retail market into criminal channels—this study utilizes a decade’s worth of data on handgun sales in the state of Maryland and subsequent recoveries of those guns by police in order to identify the characteristics of firearms, sellers, buyers, and sales transactions that predict whether a gun is used in crime subsequent to purchase. The study provides some of the most sophisticated evidence to date on crime use risks associated with high-risk buyers, problem gun dealers, preferred crime guns, purchases involving multiple guns, and other suspected trafficking indicators. The study is based on three sets of analyses: 1) analysis of 235,011 handgun sales in Maryland from 1990 through October 1999 and 7,575 recoveries of those guns reported by police throughout the nation to the federal Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) from 1990 through March 2000; 2) analysis of 71,956 handgun sales in the Baltimore metropolitan area from 1994 through October 1999 and 1,850 recoveries of those guns reported by Baltimore police to ATF from 1994 through March 2000; and 3) analysis of 48,039 handgun sales in the Maryland counties of the Washington, D.C. metropolitan area from 1994 through October 1999 and 529 recoveries of those guns reported by D.C. police to ATF from 1994 through March 2000.

Philadelphia: Jerry Lee Center of Criminology University of Pennsylvania, 2007. 96p.

By Aaron Karp

Uncertainty about any firearms data requires systematic estimation that relies on a broad spectrum of sources and makes approximation unavoidable. The Small Arms Survey’s estimates of civilian firearms holdings use data gathered from multiple sources. However, with much of civilian ownership concealed or hard to identify, gun ownership numbers can only approximate reality. Using data from several different sources, at the end of 2017 there were approximately 857 million civilian-held firearms in the world’s 230 countries and territories. Civilian firearms registration data was available for 133 countries and territories. Survey results were used to help establish total gun civilian holdings in 56 countries. The new figure is 32 per cent higher than the previous estimate from 2006, when the Small Arms Survey estimated there were approximately 650 million civilian-held firearms. Virtually all countries show higher numbers, although national ownership rates vary widely, reflecting factors such as national legislation, a country’s gun culture, historical and other factors. While some of the increase reflects improved data and research methods, much is due to actual growth of civilian ownership.

Geneva: Small Arms Survey, 2018. 12p.

By John J. Donohue, Abhay Aneja and Kyle D. Weber

This paper uses more complete state panel data (through 2014) and new statistical techniques to estimate the impact on violent crime when states adopt right-to-carry (RTC) concealed handgun laws. Our preferred panel data regression specification, unlike the statistical model of Lott and Mustard that had previously been offered as evidence of crime-reducing RTC laws, both satisfies the parallel trends assumption and generates statistically significant estimates showing RTC laws increase overall violent crime. Our synthetic control approach also strongly confirms that RTC laws are associated with 13-15 percent higher aggregate violent crime rates ten years after adoption. Using a consensus estimate of the elasticity of crime with respect to incarceration of 0.15, the average RTC state would need to roughly double its prison population to offset the increase in violent crime caused by RTC adoption.

Cambridge, MA; National Bureau of Economic Research, 2018. 126p.

By Philip J. Cook, Harold A. Pollack and Kailey White

Chicago became infamous for high rates of gun violence during the Tommy Gun era of the Roaring ‘20s. While Tommy Guns are rare these days, Chicago continues to have relatively high rates of lethal violence, almost all involving guns. Homicide rates in Chicago hit a post-War peak during the Crack epidemic circa 1992, and declined thereafter. But other cities, most notably New York and Los Angeles, experienced far greater reductions in violence, as did the nation as a whole. Then in 2016, Chicago experienced a spike in gun violence, with the homicide rate increasing year over year by 58% (University of Chicago Crime Lab, 2017). Reducing gun violence, already a priority for city leaders, has become still more urgent. There was also a nationwide surge in gun violence between 2014 and 2016, raising the question of whether the long downward trend in violence has reversed. What can be done? There are two basic law enforcement strategies for reducing gun violence. The first is through police and court efforts, both reactive and proactive, to deter gun misuse directly. Those efforts entail improved investigation capacity to increase the arrest and conviction rates for gun assault, but also proactive tactics to discourage illicit gun carrying. The second strategy is targeted on illicit gun transactions that arm people who might harm others. The goal is to make guns scarcer to anyone legally disqualified from buying them, including youth and people with prior felony convictions. Crafting an effective supply-side strategy requires a good understanding of how people who might harm others currently procure their guns. Providing that baseline information is the motivation for this project.

Chicago: University of Chicago Crime Lab, 2018. 152p.

By Philip J. Cook and Jens Ludwig

The National Survey of Private Ownership of Firearms took place during November and December 1994 to gather information on the size, composition, and ownership of the gun stock in the United States; how and why guns are acquired; gun storage and carrying; and the defensive use of firearms against criminal attackers.

This national telephone survey used a list-assisted random-digit-dialing sampling method and produced a response rate of 44 percent or 59 percent, depending on the definition used. Results revealed that an estimated 192 working firearms are in private possession; about one-third of these are handguns. At least 40 percent of all handguns are semi-automatics. Only about 1 in 6 handguns have barrel lengths shorter than 3 inches. About one-fourth of adults personally own a firearm; this finding includes 42 percent of men and 9 percent of women. Gun ownership may be less popular among younger adults than among those ages 51 or older. Gun ownership is also most prevalent among middle-aged, middle-class white people from rural areas. Adults who have been arrested for a non-traffic offense are more likely to own a firearm than are other adults. In addition, about 10 percent of the adults own about 77 percent of the total stock of firearms. Overall, 46 percent of gun owners own some kind of gun primarily for protection against crime. Almost all owners report receiving some kind of instruction in the use of their firearms. About one in five of all gun-owning households keep a loaded and unlocked gun in the home. About one in six handguns are kept on the owner's person or in a motor vehicle. Estimates of defensive use of guns are similar to those of Kleck and Gertz, but survey-based estimates appear to be grossly in error for several reasons.

Washington, DC: Police Foundation, 1996. 112p.

By Abhay Aneja, John J. Donohue III and Alexandria Zhang

For over a decade, there has been a spirited academic debate over the impact on crime of laws that grant citizens the presumptive right to carry concealed handguns in public – so-called right-to-carry (RTC) laws. In 2004, the National Research Council (NRC) offered a critical evaluation of the “More Guns, Less Crime” hypothesis using county-level crime data for the period 1977-2000. 15 of the 16 academic members of the NRC panel essentially concluded that the existing research was inadequate to conclude that RTC laws increased or decreased crime. One member of the panel thought the NRC's panel data regressions showed that RTC laws decreased murder, but the other 15 responded by saying that “the scientific evidence does not support” that position.

We evaluate the NRC evidence, and improve and expand on the report’s county data analysis by analyzing an additional six years of county data as well as state panel data for the period 1979-2010. We also present evidence using both a more plausible version of the Lott and Mustard specification, as well as our own preferred specification (which, unlike the Lott and Mustard model presented in the NRC report, does control for rates of incarceration and police).

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  While we have considerable sympathy with the NRC’s majority view about the difficulty of drawing conclusions from simple panel data models and re-affirm its finding that the conclusion of the dissenting panel member that RTC laws reduce murder has no statistical support, we disagree with the NRC report’s judgment on one methodological point: the NRC report states that cluster adjustments to correct for serial correlation are not needed in these panel data regressions, but our randomization tests show that without such adjustments the Type 1 error soars to 22 - 73 percent.

  Our paper highlights some important questions to consider when using panel data methods to resolve questions of law and policy effectiveness. We buttress the NRC’s cautious conclusion regarding the effects of RTC laws by showing how sensitive the estimated impact of RTC laws is to different data periods, the use of state versus county data, particular specifications (especially the Lott-Mustard inclusion of 36 highly collinear demographic variables), and the decision to control for state trends.

Cambridge, MA: National Bureau of Economic Research, 2012. 109p.

by Mary Allen, Canadian Centre for Justice and Community Safety Statistics

In 2020, consistent with historical trends, violent Criminal Code offences accounted for about one in every five crimes that came to the attention of police. Firearm-related violent crime typically represents less than 3% of police-reported violent crime in Canada; nevertheless, it has a significant emotional and physical impact on victims, families and communities. Additionally, rates of firearm-related violence have seen a general increase over the past several years.

Concern about gun crime is long standing and a variety of approaches have been used to address it, including changes in legislation (see Text box 1). In April 2020, 22 people were killed in a mass shooting in Nova Scotia, the deadliest mass shooting in Canada in recent years. In particular, the Nova Scotia shooting led to a ban on assault-style firearms and renewed discussions around gun control and access to illegal weapons.

Mayors Against Illegal Guns

This report provides a comprehensive review of Stand Your Ground laws and how they have affected public safety and the criminal justice system. It explains how Stand Your Ground statutes have dramatically expanded the circumstances under which people are permitted to use deadly force and have created legal hurdles that make it more difficult for law enforcement to hold shooters accountable. The report also shows that Stand Your Ground states have on average experienced a 53% increase in homicides deemed justifiable in the years following passage of the law, compared with a 5% decrease in states without Stand Your Ground statutes during the same period — an increase disproportionately borne by the black community. Finally, the report provides a state-by-state analysis of each of the 22 state Stand Your Ground laws.

New York: National Urban League, 2013. 28p.

By Scott R. Kegler; Deborah M. Stone; James A. Mercy and Linda L. Dahlberg

Firearm homicides and suicides represent an ongoing public health concern in the United States. During 2018–2019, a total of 28,372 firearm homicides (including 3,612 [13%] among youths and young adults aged 10–19 years [youths]) and 48,372 firearm suicides (including 2,463 [5%] among youths) occurred among U.S. residents (1). This report is the fourth in a series* that provides statistics on firearm homicides and suicides in major metropolitan areas. As with earlier reports, this report provides a special focus on youth violence, including suicide, recognizing the magnitude of the problem and the importance of early prevention efforts. Firearm homicide and suicide rates were calculated for the 50 most populous U.S. metropolitan statistical areas (MSAs)† for the periods 2015–2016 and 2018–2019, separated by a transition year (2017), using mortality data from the National Vital Statistics System (NVSS) and population data from the U.S. Census Bureau. Following a period of decreased firearm homicide rates among persons of all ages after 2006–2007 in large metropolitan areas collectively and nationally, by 2015–2016 rates had returned to levels comparable to those observed a decade earlier and remained nearly unchanged as of 2018–2019. Firearm suicide rates among persons aged ≥10 years have continued to increase in large MSAs collectively as well as nationally. Although the youth firearm suicide rate remained much lower than the overall rate, the youth rate nationally also continued to increase, most notably outside of large MSAs. The findings in this report underscore a continued and urgent need for a comprehensive approach to prevention. This includes efforts to prevent firearm homicide and suicide in the first place and support individual persons and communities at increased risk, as well as lessening harms after firearm homicide and suicide have occurred.

Atlanta, GA: Centers for Disease Control, 2022. 7p.