By Zachary Porreca

I demonstrate the linkage between gentrification and gun violence. As the underlying mechanism, I focus on gentrification's displacement effect on local drug markets. Using two-way fixed effects differences-in-differences estimators, I show the gentrification of one block increases violence across the surrounding neighborhood. I find that some 2,400 (8%) of Philadelphia's shootings between the years 2011 and 2020 can be attributed to spillover effects from the gentrification of drug blocks. This effect is nearly ten times stronger than that observed on blocks without high levels of drug crime. This study also contributes a new empirical measurement of gentrification drawn primarily from property sales, along with building, zoning, and alteration permit issuance and utilizes a novel nearest-neighbor network approach to identify spatial spillover effects.

Unpublished Paper, 2021, 53p.

By Silvia Villarreal, Amy Barnhorst, Richard Bonnie, Kami Chavis, Cassandra Crifasi, Shannon Frattaroli, Kelly Roskam, Jeffrey Swanson, Sylvia Washington, and Joshua Horwitz.  

  Firearm purchaser licensing (FPL) laws (sometimes referred to as permit-to-purchase) require an individual to obtain a license through an application process before purchasing a firearm. They are among the most effective policies at reducing gun violence. FPL laws create robust mechanisms of accountability among both prospective gun owners and sellers to ensure that those disqualified from firearm ownership can’t legally obtain a gun. This report compiles existing research to inform state policy. It includes an overview of state FPL laws and recommends core components of FPL laws to maximize public health benefits.

The authors recommend that state gun licensing laws include five core components to maximize public health benefits:

• Firearms safety training

• Fingerprinting

• In-person application

• Comprehensive background checks

• Waiting periods between application and possession of a firearm

Currently 11 states—Connecticut, Delaware, Hawaii, Illinois, Maryland, Massachusetts, Michigan, Nebraska, New Jersey, New York, and Oregon—and Washington, D.C., have active firearm purchasing licensing laws. Of these, five states—Delaware, Hawaii, Massachusetts, New Jersey, Oregon—and Washington, D.C., have the five components recommended in the report.

“There is solid evidence from public health research suggesting that when states adopt firearm purchaser licensing laws with measures such as mandatory safety training, comprehensive background checks, and waiting periods, reductions in gun-related homicides and suicides follow,” says study lead author Silvia Villarreal, MPP, director of research translation at the Johns Hopkins Center for Gun Violence Solutions.

Gun violence is a significant cause of mortality for Americans, and the leading cause of death for children and young people ages 1 to 17. According to the Centers for Disease Control and Prevention, 46,728 people died from gunshots in the U.S. in 2023, the most recent year for which final statistics are available. The 2023 CDC data shows firearms were used in seven out of 10 homicides and 55% of suicides.

U.S. federal law requires background checks for would-be gun buyers at federally licensed gun stores but does not cover private sales or gun shows. Moreover, federal law generally allows a gun sale to proceed if the background check is still pending after three business days. 

The report cites evidence—in many cases generated by the report’s co-authors—that firearm purchaser licensing reduces gun violence. A 2018 study linked gun purchaser licensing laws to an 11% reduction in gun homicides in urban counties across the U.S. from 1984 to 2015. A 2020 study found that gun purchaser licensing laws were associated with 56% fewer mass shooting incidents and 67% fewer mass shooting victims on average. Another 2020 study linked Connecticut’s 1995 handgun purchaser licensing law to a 28% drop in the state’s gun homicide rate and a 33% drop in its gun suicide rate from 1996 to 2017.

Similarly, a 2014 study found that Missouri’s 2007 repeal of its handgun-buyer licensing law was followed by 25% increase in its gun homicide rate in the five years following enactment. A 2015 study found a 16% increase in Missouri’s gun suicide rate in the five years following the repeal.

“This report is an important resource that brings together the research, policy, and legal considerations about firearm purchasing laws,” says Josh Horwitz, JD, co-director of the Center for Gun Violence Solutions. “Our intent is to give policymakers and advocates all the guidance and evidence they need to bring these policies to fruition.” 

The researchers hope that the report will encourage state policymakers to maintain or strengthen existing firearm-purchaser licensing laws and enact firearm purchasing laws in states that don’t yet have them.

Baltimore, MD: The Johns Hopkins Center for Gun Violence Solutions 2025. 30p.

By Ellicott C. Matthay, Ariana N. Gobaud, Charles C. Branas, Katherine M. Keyes, Brita Roy, Magdalena Cerdá

  BACKGROUND: Firearm violence remains a leading cause of death and injury in the United States. Prior research supports that alcohol exposures, including individual-level alcohol use and alcohol control policies, are modifiable risk factors for firearm violence, yet additional research is needed to support prevention efforts. OBJECTIVES: This scoping review aims to update a prior 2016 systematic review on the links between alcohol exposure and firearm violence to examine whether current studies indicate causal links between alcohol use, alcohol interventions, and firearm violence-related outcomes. ELIGIBILITY CRITERIA: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) guidelines, a comprehensive search of published studies was conducted, replicating the search strategy of the prior review but focusing on studies published since 2015. The review included published studies of humans, conducted in general populations of any age, gender, or racial/ethnic group, that examined the relationship between an alcohol-related exposure and an outcome involving firearm violence or risks for firearm violence. Excluded were small studies restricted to special populations, forensic or other technical studies, non-original research articles such as reviews, and studies that relied solely on descriptive statistics or did not adjust for confounders. SOURCES OF EVIDENCE: The review included published studies indexed in PubMed, Web of Science, and Scopus. Eligible articles were published on or after January 1, 2015. The latest search was conducted on December 15, 2023. CHARTING METHODS: Using a structured data collection instrument, data were extracted on the characteristics of each study, including the dimension of alcohol exposure, the dimension of firearm violence, study population, study design, statistical analysis, source of funding, main findings, and whether effect measure modification was assessed and, if so, along what dimensions. Two authors independently conducted title/abstract screening, full-text screening, and data extraction until achieving 95% agreement, with discrepancies resolved through discussion. RESULTS: The search yielded 797 studies. Of these, 754 were excluded and 43 met the final inclusion criteria. Studies addressed a range of alcohol exposures and firearm violence-related outcomes, primarily with crosssectional study designs; 40% considered effect measure modification by any population characteristic. Findings from the 21 studies examining the relationship of individual-level alcohol use or alcohol use disorder (AUD) with firearm ownership, access, unsafe storage, or carrying indicated a strong and consistent positive association. Seven studies examined associations of individual-level alcohol use or AUD with firearm injury or death; these also indicated a pattern of positive associations, but the magnitude and precision of the estimates varied. Eight studies examined the impact of neighborhood proximity or density of alcohol outlets and found mixed results that were context- and study design-dependent. Two studies linked prior alcohol-related offenses to increased risk of firearm suicide and perpetration of violent firearm crimes among a large cohort of people who purchased handguns, and two studies linked policies prohibiting firearm access among individuals with a history of alcohol-related offenses to reductions in firearm homicide and suicide. Finally, four studies examined alcohol control policies and found that greater restrictiveness was generally associated with reductions in firearm homicide or firearm suicide. CONCLUSIONS: Findings from this scoping review continue to support a causal relationship between alcohol exposures and firearm violence that extends beyond acute alcohol use to include AUD and alcohol-related policies. Policies controlling the availability of alcohol and prohibiting firearm access among individuals with alcohol-related offense histories show promise for the prevention of firearm violence. Additional research examining differential impacts by population subgroup, alcohol use among perpetrators of firearm violence, policies restricting alcohol outlet density, and randomized or quasi-experimental study designs with longitudinal follow-up would further support inferences to inform prevention efforts.

Alcohol Research: Current Reviews,  2025;45(1):01, 29p.

By Annelies Pauwels and Merlina Herbach

This policy brief examines the methods of firearms acquisition by right-wing extremists (RWEs) in Europe between 2019 and 2024. Based on a dataset of 118 cases, it reveals that RWEs resort to diverse legal and illegal acquisition strategies, including the use of illicit markets, legal possession, theft from military and law enforcement sources, and private manufacture, particularly 3D printing. The policy brief further discusses current EU countermeasures and their effectiveness in addressing RWE-specific acquisition methods. It identifies gaps in existing policies and enforcement, particularly regarding background checks in issuing and reviewing weapon licences, screening of military and law enforcement personnel, and regulation of emerging technologies like 3D printing. The authors call for further research to increase the understanding of the RWE-firearms nexus and to develop more targeted prevention strategies.

The Hague: The International Centre for Counter-Terrorism (ICCT), 2024, 30p.