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The Fight Against Rampant Gun Violence: Data-Driven Scientific Research Will Light the Way

Date Published
December 2, 2021

A data point will not stop a bullet, but evidence-based research grounded in reliable science is a proven pathway for addressing the gun violence crisis in the United States.

For a quarter century, studies supported by the National Institute of Justice (NIJ) have made clear that multifaceted, data-driven, strategic approaches to firearms violence research have the potential to stem gun traffic, cut down on shootings, and save lives. In several communities, they have already done so.

A recent exhaustive study of motivations for gun possession and use by young people in violence-torn sections of three New York City boroughs confirms that fear and the desire for physical safety, more than any criminal inclination, drive young people to carry and use firearms. Another recent NIJ-supported study, made possible by quantum leaps in computing power, has harnessed big data to help measure the impact of socioeconomic factors and specific physical features of an urban environment—like gas stations and overgrown lots—on gun violence.

More new research has examined how delinquent youths’ firearm involvement influences later criminal gun use and their own victimization in young adulthood. And yet another recent NIJ-supported project has helped illuminate the illicit procurement path of guns used in street crimes. The vast majority of those guns come from illegal sources, and the study traced how they move through underground markets, with an eye toward refined interdiction strategies.

On many fronts, the research continues, bolstered by an influx of new federal resources responding to a national gun violence epidemic. A second straight year of surging firearms violence on U.S. streets, leaving thousands dead and many more injured, underscores the magnitude of the task of finding effective policy and practice solutions.

In response, the administration unfurled a comprehensive strategy on gun violence designed to put more police on the streets to fight crime, invest in community policing, fight the inflow of illicit weapons used in crimes, and rebuild police legitimacy and trust in the communities they serve. New initiatives are designed to better address the root social causes of crime, such as poverty, educational inequities, and the lack of jobs and training in urban communities.

Of the many program elements the U.S. Department of Justice will spearhead, a centerpiece is an enhanced Project Safe Neighborhoods (PSN). PSN brings together local, state, and federal law enforcement officials, prosecutors, and community stakeholders. The project’s purpose is to identify the most pressing violent crime issues in an area and collaborate on comprehensive solutions.

PSN is a gun violence abatement tool ready for use today because past federally backed scientific research verified its potential and identified ways to improve. The PSN model was implemented in 2001; a second version, recently adopted, incorporates findings from rigorous evaluation research on the original design. Evaluations of the original PSN model established it as a promising evidence-based crime prevention tool, while identifying areas for improvement.

Both the new insights from recent NIJ-supported research and the lessons distilled from the agency’s research archive point to the foundational role science must play in justice stakeholders’ collective response to street violence. Evidence-based research on who carries guns in high-crime areas, how they get them, and how and where they use them, as well as the personal damage done by firearms, will continue to inform real-world solutions to the gun epidemic and the needs of violence victims.

The research archive also points to the value of gun violence incident reports as a window to solutions.[1] NIJ staff scientists reviewing the archive concluded that incident review teams can significantly advance the understanding of gun violence and help law enforcement identify patterns of people, groups, places, and contexts driving that violence. That approach is particularly effective in understanding how criminal, nonfatal shootings relate to gun homicides, mainly because of insufficient administrative data on nonfatal shootings, according to the research. The lessons drawn from incident reports suggest that criminal, nonfatal shooting analyses should be part of a larger crime reduction strategy.[2] Comprehensive nonfatal shooting data can assist law enforcement in understanding the context of local gun violence and inform policy and practice, the research suggests.

For all the research progress to date, significant gaps persist. Still lacking in the NIJ-supported research literature, for instance, are theoretical generalizations about those circumstances that lead some elements of society to engage in and persist in firearms violence.

This article first selectively focuses on results of more recent gun violence research managed by NIJ, the scientific research, development, and evaluation branch of the U.S. Department of Justice. It then concisely reviews representative lessons gained from NIJ-supported firearms violence research begun in the 25 years from 1991 to 2016, highlighting scientific evaluations of the original Project Safe Neighborhoods and other program models found to be promising against gun violence. It concludes by reflecting on the lessons to be broadly drawn from both micro- and macro-level studies of gun violence. Micro-level research focuses on individuals who perpetrate crimes and victims. Macro-level studies, on the other hand, tend to point to the benefits of, and need for, high-level cross-collaborations that can drive policy and practice reforms and make a systemic impact on gun culture.

Motivations for Gun Possession and Use in NYC

Recent comprehensive research on the motivations of youth who carry and use guns in high-crime New York City neighborhoods offers compelling evidence that fear, not criminal interest, is their motivator.

The study of youth who use guns was unprecedented for a scientific study in the largest U.S. city (by population), in terms of both sample size and the extent of measures taken to build trust between subjects and community-based research staff. It was designed to address the gap in generalizable studies on youth gun culture, a traditionally hidden group.

The research, conducted by the Center for Court Innovation, with results reported in 2020, examined 330 city youth at high risk for gun violence. Subjects had to have owned or carried a gun or been shot or shot at. The study population was 94 percent Black and Latino, and 79 percent lived in public housing. A history of violent victimization was a near-universal experience among study subjects.

Through in-depth interviews of participants, the study established that most possessed or used guns out of a generalized fear of being victimized or a specific fear of retaliation. A history of violence victimization also informed the decision to carry a firearm. Many also reportedly felt a pervasive fear of the state, particularly law enforcement.

In the end, the study report concluded, most participants said they carried guns to increase their feelings of safety. “They held a widespread belief that they could be victimized at any time, and guns served to protect them from real or perceived threats from other gun carriers.”

The study’s parsing of motivations behind young people’s resorting to firearms also plainly supports a conclusion that people of limited means want the same things as people of means and resort to crime to attain them.

On the basis of their findings, the study team recommended specific approaches to working with young people to reduce gun violence. Key recommendations include

  • Organizations should bring services to spaces important to youth, such as project courtyards.
  • Organizations should hire credible messengers for interactions with youth.
  • Community safety strategies that do not involve law enforcement should be adopted.
  • Jobs should be created specifically for this youth population, with concrete pathways to jobs that pay a living wage.

Firearm Involvement in Delinquent Youth and Collateral Consequences in Young Adulthood

A team of researchers from the Northwestern University recently examined the association between firearm involvement by youth involved in the juvenile justice system and subsequent firearm violence in adulthood.[3] The research advanced the work of the federally funded Northwestern Juvenile Project, a large-scale longitudinal study of delinquent youth’s lives after detention. That study looked at the gun involvement of nearly 2,000 people who entered the juvenile justice system as adolescents in Cook County, Illinois.

The researchers found that, for the urban sample of Cook County youth who were both arrested and detained, involvement with firearms during adolescence—including victimization—is a significant risk factor for criminal firearm perpetration and ownership during adulthood. The authors concluded that there is a need for programs that target high-risk youth, in addition to targeting the neighborhoods where they live. Expanding prevention and intervention programs for individuals and communities enhances firearm violence reduction efforts when carried out by law enforcement in tandem with the public health system, researchers emphasized.

Underground Markets as a Supply Chain of Guns to People at the Highest Risk of Using Them in Violent Crimes

A study of underground gun markets examined how firearms are funneled to people in Chicago who are at the highest risk of using them in violent crimes.[4] Through the collection and analysis of several unique sources of qualitative and quantitative data, the research team from the University of Chicago Crime Lab determined the following:

  • Guns confiscated by the police from gang members tend to be quite old, with an indication that they move through a series of transactions before being acquired by the current owner, according to an examination of crime gun trace data provided to the Chicago Police Department by the federal Bureau of Alcohol, Tobacco, Firearms and Explosives. Most gang guns come from out of state or through intermediaries in the underground market, including straw purchasers, brokers, and traffickers.
  • Data derived from semi-structured interviews with 221 males sentenced for gun or weapons charges and incarcerated in Illinois revealed that respondents were extensively involved with guns and violence, albeit virtually none were eligible for an Illinois gun license. Most reported obtaining guns from voluntary transactions involving purchases, trades, loans, gifts, or sharing arrangements with their close and trusted social network. Theft also played a role (7 percent reported stealing a firearm). Ammunition was also mainly acquired from trusted street sources or straw purchases. Guns and ammunition are easy to obtain, the interviews established. Lastly, respondents expressed mistrust of law enforcement and unwillingness to cooperate.
  • Another study component examined the details of gun transactions between first sale and last acquisition by someone who used the gun in a criminal act. The study element used structured interviews of key players in gun distribution, including gang members, gun brokers who sell guns to the public, and “gun runners” who move large quantities of guns between areas. The research found that underground gun markets may be thought of as social webs of individuals who play varied, but crucial, roles in the illegal distribution of firearms. The connections are built on familiarity and trust, with individuals often required to provide references to gain entry to the network.
  • Notably, although gang cohesion in Chicago was dropping, gangs were becoming more engaged in gun distribution to both gang members and individuals not in gangs.
  • Another noteworthy finding was that a resigned attitude about gun violence occurring in a community was most prevalent among those residing outside the community. Those living inside the affected neighborhoods tended to look forward to a positive social change and to actively working toward creating safer neighborhoods.
  • The research team also documented the revival of a historic practice, that is, engagement of at-risk individuals in ancillary gun-related activity, such as storing weapons, providing safe spaces for gun transactions, and acting as a lookout for police. These services can enable cash-strapped individuals to obtain immediate off-the-books revenue. Nearly all subjects were unemployed or working part-time in menial jobs.

These findings, the authors concluded, suggest a fundamental shift in the ways that crime guns are acquired. In contrast to the old pattern, when guns were often purchased through federally licensed dealers, it is now very rare for a crime gun to be bought new from a gun dealer in a documented sale.[5] Because other intermediaries in the underground market are now in place—straw purchasers, brokers, and traffickers—it is important for law enforcement to focus on those groups, the research suggests, in order to reduce gang access to guns. Further, by partnering and collaborating with other key stakeholders, law enforcement could advance strategies aimed at reducing gun violence. Building trust between law enforcement and affected neighborhoods will be essential to effective collaboration, the study concluded.

The Built Environment and Gun Violence

Another significant newer study, completed for NIJ in June 2021 by the RAND Corporation, was developed to give cities a new tool for fighting firearms violence through a better understanding of commonalities among the “built environment” (gas stations, overgrown lots, bars, convenience stores, etc.), the socioeconomic traits of a neighborhood population, and violence.

The RAND team sought to build on the established fact that fatal shootings tend to be heavily clustered in urban neighborhoods. The goal was to develop insights on geospatial associations between the built environment and gun violence, a connection previously not well understood due to a lack of adequate data. Powerful new computing capacity and data-sharing capabilities enabled the research team to generate the volumes of data needed for a close analysis of many built features in relation to socioeconomic traits.

One study element of interest, identified as ripe for more research, was local perceptions by community members of the influence of the built environment and socioeconomic factors on gun violence. To that end, in each of four cities—Detroit, Los Angeles, New Orleans, and Pittsburgh—two focus groups of community members were convened to identify those factors that the community members associate with firearm violence and general crime and that urban planners would favor preventive measures to address.

The researchers found dissimilar community views across cities on the relation to the built environment features to firearm crime. For example, participants in Pittsburgh, New Orleans, and Los Angeles discussed violence as a function of poor lighting, but those in Pittsburgh and Los Angeles also associated gun violence with broad daylight. Perceptions differed widely on a number of violence-related factors across the four cities.

There were reported common themes, however. Participants had concerns about overgrowth in lots, lack of lighting, and loitering in all four cities. Participants viewed both isolation and crowded areas as dangerous for different reasons. In all cities, participants associated activities such as prostitution, drugs, and violence with built environment features that lead to firearm violence specifically.

A key implication of the research, given the absence of specific similarities relating violent crime to the built environment, is that there will not be a one-size-fits-all solution. As a result, the research report noted, each city’s separate findings will be important when that city’s urban planners and law enforcement determine how the built environment and socioeconomic factors should inform solutions to gun violence.

Lessons from the NIJ Archive: Collaborative, Multifaceted Programs Built on Data-Driven Research Can Work

Since the 1980s, NIJ has supported scientific evaluations of the effectiveness of programs and policies to reduce firearms violence. Those programs and policies, developed for adoption or enhancement by state and local justice agencies often working with federal partners, have included the following:

  • Collaborative strategic approaches to reducing violence through prevention, disruption, deterrence, or a combination of factors.
  • Community-based firearm violence prevention and intervention programs.

Findings from 92 identified final study reports, including basic research and program evaluations, and related publications on firearms research supported by NIJ and initiated between 1991 and 2016, were the subject of a recent agency science staff analysis. That review broke down research focus areas by subject and assessed common themes and findings.[6]

On balance, the retrospective review revealed that the more strategic, aggressive approaches grounded in data, research, collaboration, and partnerships are implemented, the fewer instances of firearms-related crimes and homicides are reported.[7]

Challenging Stereotypes

The reviewed research primarily examined the prevalence of firearms among inner-city youth populations at the highest risk of gun violence. Final reports from relevant projects challenged then-common stereotypes regarding gun possession and use by urban youth. One persistent stereotype was the notion that juveniles arm themselves primarily because of the needs of criminal activity, drug trafficking, and gang affiliations. More often, the studies suggested, juveniles seek firearms out of fear rather than criminal need. (The newer New York City study, discussed above, substantially reinforces that conclusion, backed by unprecedented data volume and new research methods creating a critical trust factor for participants.)

An overarching theme of the reviewed scientific studies was that the gun and gang culture gripping U.S. inner cities is largely a function of the social alienation of young people. Guns, drugs, gangs, crime, and violence are all expressions of the pervasive alienation of youth from the conventions of the larger society. The NIJ reviewers also observed a common conclusion among researchers that inner-city youths’ perception of guns as necessary to survival will endure unless attention is given to conditions that promote insecurity and fear and breed feelings such as hostility and hopelessness.

The reviewed catalog of research also shows that illegally acquired firearms are disproportionately related to firearm violence in the United States, as compared to those acquired legally. A shift in the means of acquiring guns by prohibited persons has also been noted. (The newer University of Chicago Crime Lab study, discussed above, substantially reinforces that conclusion.)

Examples of Evaluated Programs That Made Inroads Against Gun Possession and Use

The archival review highlighted research-validated program successes in reducing gun possession and violent crime. A prominent example follows:

Original Project Safe Neighborhoods. Partnerships led by the U.S. attorney in each of the nation’s 94 federal judicial districts to reduce violent crimes by, among other measures, addressing criminal gangs and felony firearm possession.

In May 2021, the U.S. Department of Justice announced a strategy to strengthen Project Safe Neighborhoods by adopting new core principles, including fostering trust and legitimacy in communities, supporting community organizations that help prevent violence, setting strategic enforcement priorities, and measuring results. The announcement emphasized that the project’s goal is to reduce crime and not to increase arrests and prosecutions, as if they were ends in themselves.

In 2012, CrimeSolutions, the online NIJ resource that rates justice system programs and practices on the basis of scientific evaluations, rated the original Project Safe Neighborhoods as “Promising.” The long-standing program has not been evaluated in more than a decade, and the program has changed significantly since then. Currently, an NIJ-funded, rigorous, national evaluation of the enhanced program, with a focus on 10 program sites, is being carried out by RTI International. The research team aims to pin down how Project Safe Neighborhoods affected violent crime across the United States, in individual districts, and in targeted enforcement areas.

Other landmark interventions evaluated through NIJ-funded projects include Operation Ceasefire, the Kansas City (MO) Gun Experiment, and Strategic Approaches to Community Safety Initiative (SACSI). Their promise for reducing gun violence has been established through rigorous evaluations.[8]


Taken as a whole, nearly 100 reports and publications populating the NIJ firearms violence research archive represent both micro- and macro-level examinations of the U.S. gun violence problem. Micro-level research examines individual needs, actions, and impacts in relation to gun violence. At the macro- or community level, research drawing from those individual findings probes the societal implications and impacts of firearms activity as a critical step toward forging collaborative programs and partnerships that can make a lasting difference.

As both the NIJ research archive and newer studies suggest, the criminal justice system is in a unique position to help prevent firearm violence by focusing on high-risk individuals in gun crime-ridden communities. Yet, decades of data-driven research instructs that the justice system must collaborate with other systems, such as urban planning, the public health system, and key community stakeholders contributing to the socioeconomic health of communities, in order to make a lasting impact on street violence.

Micro- and macro-level approaches are equally important to maintaining a scientifically sound basis for advancing gun violence policy and practice. In the end, only evidence-based science on who carries guns illegally, why they carry and use them, and how they get them can produce the answers law enforcement, the justice system, and community groups need to take clear aim at the gun violence crisis.

Date Published: December 2, 2021