- In cities crime is highly concentrated and entrenched in a few small areas.
- Strategies to reduce crime that focus on community changes have strong theoretical and empirical support.
- The best place-based interventions reduce serious crimes by making areas less attractive to criminal behavior rather than relying on arrests or social services.
- Cleaning up blighted physical disorder in communities is key to effective crime prevention.
- Place-based interventions should be viewed as complements to effective and constitutional policing.
- Governments should provide matching grants and other incentives to encourage communities to make improvements that reduce crime.
In every city, a small group of blocks generate most of the serious crime. In Chicago, Los Angeles, and New York, for example, just 6-13% of street addresses where a crime was reported between 2021 and 2022 account for 50% of all reported crime.1 The hyper-concentration of crime is so common worldwide that Hebrew University criminologist David Weisburd refers to the “law of crime concentration.”2 Cambridge University criminologist Lawrence Sherman coined the term crime “hot spots” and noted their relative stability, suggesting the routine activities of these spaces could be “regulated far more easily than the routine activities of persons” (p. 49).3 The location of these crime hot spots is remarkably stable year after year, and when cities experience a surge in serious crime an outsized share is driven by crime hot spots. Research that examined the surge in shootings in 2020-2021 found that 47% of the rise in New York and 55% in Los Angeles occurred in only 10% of census blocks groups.4 The empirical reality of the concentration of crime in cities suggests there are features of these places that make crime endemic.
Place-based crime reduction strategies are grounded in some of the most critical insights made by crime scholars in the past forty years. They enjoy broad support across a wide range of theoretical traditions. Research by Harvard University sociologist Robert Sampson finds that crime is more concentrated in places with physical disorder in the form of dilapidated homes, poor street lighting, vacant lots, and trash-filled streets.5 Theoretical explanations of how a disordered environment impacts crime emphasize how it affects neighborly socialization and criminal opportunities. Social disorganization theory and the concept of collective efficacy, or the willingness of residents to intervene in their neighborhoods for the common good and out of shared mutual trust, suggests that physical disorder may undermine social ties that foster informal social controls that mitigate criminal behavior.6 For example, neighbors may feel less empowered to intervene when they witness illegal activities in front of a vacant house where no obvious owner is maintaining the space.
A blighted built environment may affect natural surveillance and the unconscious way informal interactions occur on streets. In the 1960s, urbanist Jane Jacobs suggested busy streets with buildings with clear sight lines down a block had less crime because there were “more eyes upon the street” by the “natural proprietors” of a community. Jacobs noted that crime mainly was prevented by the “intricate, almost unconscious, network of voluntary controls by the people themselves, and enforced by the people themselves” (p. 31).7 By emphasizing networks of informal social controls, Jacobs’ insights clearly link the built environments to collective efficacy.
The importance of the built environment in fostering crime is also explained by theories in environmental criminology, including crime prevention through environmental design (CPTED) and situational crime prevention.8 CPTED argues that the built environment makes places less attractive to motivated offenders when there are symbols of guardianship and surveillance. Situational crime prevention argues that real or symbolic signs of guardianship, such as good street lighting, can reduce crime by making an area appear less attractive to criminal offenders. Dilapidated or abandoned buildings, poor street lighting, vacant lots, and trash-filled streets link to potential crime opportunity channels, including no clear ownership, reduced surveillance, and changes in human activity that signal an area is crime-prone. Observational studies of vacant lots in Philadelphia have found these sites are particularly attractive places for open-air drug markets and excessive public drinking.9
The “broken windows” theory is also linked to collective efficacy and environmental criminology, through the idea that physical disorder engenders crime by signaling that no one is taking care of the space and that “untended property becomes fair game for people out for fun or plunder.”10 As Northwestern University criminologist Wesley Skogan notes, physical disorder erodes “the sense of mutual regard and the obligations of civility” that signal people care for a place, fostering fear of crime among residents, public withdrawal, and a cycle of decline.11 Integrating these theoretical traditions shows why a disorderly built environment is endemic in crime hot spots.
The best empirical evidence for place-based crime reduction strategies strongly supports these theoretical premises. Simply pointing out that a correlation exists between a disorderly built environment and crime hot spots is insufficient evidence that one causes the other. A reasonable argument can be made that there is a third factor that causes both a disorderly built environment and crime, such as more extensive poverty in crime hot spots. Correlational studies of crime and disorder suffer from the fundamental problem that multiple observed and unobserved variables could explain the relationship. Studies that rely on experimental or quasi-experimental designs where a program or investigator changes the built environment are more capable of establishing a causal connection between disorder and crime. Quasi-experimental studies of the built environment and crime rely on changes in some places.
In contrast, it does not occur in places nearly identical in poverty, street layout, and other observable things. Experimental studies of the built environment and crime provide even better causal evidence because places are first selected and then randomized to receive the intervention. As a result, the places receiving the built environment change are identical on average on both observable factors like poverty and unobservable factors that are more difficult to measure, like human activity on the street.
In drawing on the theoretical principles of environmental criminology, several high-quality quasi-experimental and experimental studies demonstrate the causal effect of interventions that make physical improvements to places on crime.12 These studies are important because they provide rigorous evidence that cleaning up the built environment reduces crime–and that the effects are seen in crime hot spots. Business improvement districts (BIDs), community-based organizations, and local nonprofits have developed successful place-based programs.
Business improvement districts that focus on keeping business corridors clean and safe through employing individuals to pick up litter and remove trash have been shown to reduce serious crime and violence, even in high-poverty sections of cities. For example, a study that examined the formation of BIDs in Los Angeles in the 1990s found that areas that formed BIDs that invested in private security and street cleaning saw an 11% reduction in serious crime, with the largest effects coming from an 18% reduction in robberies. The formation of BIDs was also associated with a 32% decline in arrests, suggesting that the crime control reductions were not a result of increasing the use of the criminal justice system. The effects estimated from this study were relative to nearby neighborhoods with comparable demographics, poverty, and crime levels. And, because the study examined changes after BID implementation, the timing of BID operations caused the crime and arrest rates to drop. The study also investigated whether crime and arrests were simply displaced to adjacent neighborhoods, finding no rise in crime or arrests in neighboring areas. In terms of cost-benefit calculations, the results suggest that an additional $10,000 spent by BIDs on crime control activities generates over $200,000 in societal benefits from crime reduction.13
Street lighting is another place-based intervention supported by high-quality evidence. For example, an experiment was conducted in New York City where 39 of the city’s public housing developments with the highest crime rates were randomly assigned to have enhanced street lights. The study found that the 39 public housing developments that received the enhanced lights, compared to a control group of public housing projects that did not receive enhanced lights, experienced a 36% reduction in nighttime crime and a 24% reduction in arrests.14 A more recent study of these same housing projects found that the crime and arrest reduction benefits persisted for three years after the lights were installed.15 This experiment provides rigorous evidence of the causal effects of enhanced street lights, consistent with several older quasi-experimental studies that found installing enhanced street lights reduced crime in commercial and residential blocks in Atlanta, Milwaukee, Fort Worth, and Kansas City.16
Quasi-experimental studies in multiple contexts have demonstrated that cleaning and greening vacant lots reduces gun violence and other serious forms of crime.17 An experiment in Philadelphia that randomly assigned 380 vacant lots to be cleaned and greened found that the greening intervention significantly reduced serious crime and shootings nearby relative to a control group that received no intervention. Notably, there was no evidence of serious crime and shootings being displaced to nearby blocks. Residents surveyed near cleaned and greened vacant lots also reported reduced perceptions of crime, vandalism, and safety concerns about going outside at night. Residents also reported increased use of outside spaces for relaxing and socializing.18
A recent experiment examined what would happen if abandoned houses were remediated to comply with Philadelphia’s ordinance that requires installing working windows and doors on all housing, whether abandoned or not. The study randomly assigned 58 abandoned houses to be remediated with working windows and doors. Compared to other abandoned houses that were assigned no treatment the study found significant reductions in gun violence. There was also no evidence of gun violence being displaced to nearby areas. The reductions in gun violence appear to be the result of changes in the appearance of disrepair around houses before and after the intervention.19
The place-based interventions that are effective at reducing serious crime share a focus on changing the situational environment to make areas less attractive to criminal behavior rather than relying on police arrests or social service strategies. Place-based programs that focus on expanding BIDs, landscape maintenance, enhanced street lighting, and abandoned housing remediation should be launched in distressed cities across the country facing rising violence in their highest crime areas. Getting these programs started requires hiring the necessary personnel and scaling up their operations. In many cities, community-based nonprofits that know how to scale these interventions exist. The key to success is having a regulatory framework and incentives to help community-based nonprofits make meaningful changes to places that will reduce crime. In the 1990s cities encouraged BIDs to form by offering tax exemptions and grants to help them get started.
However, complex tax assessments and grants are often beyond the reach of local nonprofit organizations that are key to placemaking operations. Federal investment could occur through creating a grant program to directly implement CPTED programs that are evidence-based and focused on the highest crime city blocks. The grants could be awarded to local nonprofits where the funds are used to pay for the direct services of hiring personnel that engage in trash and litter removal, abandoned housing remediation, vacant lot greening, and installation of enhanced lighting. Each city could identify a set of their highest crime city blocks that would be the focus of the grant and then pass the funds to the local community-based nonprofits to engage in this work. A smaller share of the grants could also be spent on community kickoff/engagement activities to successfully launch the CPTED projects. This would help local community members bond and recognize that new investments are coming to their streets, which is key to establishing informal social control of spaces.
An example of a grants program through which cities pass resources to direct services is the BID program in Los Angeles. The City of Los Angeles collects the assessment fees through property taxes on businesses and then passes that money to the local BIDs for their proposed service activities. The BID model was successful in the 1990s and should be expanded in cities. This means providing federal support through federal tax deductions for businesses that pay BID assessment fees for newly formed BIDs in the highest crime commercial corridors. A tax deduction that offsets BID assessments could help BIDs form in commercial corridors that historically cannot afford to pay into a local assessment.
Focusing on place-based interventions helps reduce the need for the police to repeatedly respond to crime and disorder at the same addresses. An experiment on problem-solving policing in Lowell, Massachusetts, conducted by University of Pennsylvania criminologist Anthony Braga, found police were the most effective at reducing crime in hot spots when they focused on situational strategies related to disorder (getting the city to sweep the streets for trash, graffiti removed, securing abandoned buildings, and cleaning vacant lots). These situational strategies were more effective at reducing crime than extra police presence alone.20 Place-based interventions in distressed neighborhoods complement practical and constitutional policing. A recent study finds that low income tax credits that spur new developments in places results in the police spending more time in these areas trying to keep them safe.21 Similarly, one can imagine that many place-based programs, when successful, will engender collective efficacy and make neighbors more willing to call the police when they see criminal activity occurring in public spaces. Targeted placed-based changes can reverse the spiral of decay in crime hot spots.
Today, a growing body of high-quality science demonstrates that changing places can have an essential public safety benefit that complements police. Moreover, these changes do not require significant upfront investments. They require local partnerships with municipal services, community nonprofits, and business organizations to address cleaning up blighted blocks, installing better lighting, and securing abandoned buildings. Addressing these problems block-by-block can reap dramatic positive benefits. Given that crime and related issues are highly concentrated in the same places, strategic planning can have large-scale population benefits. Improving the physical environment can help restore the communities’ vibrancy and livability.
- Based on calculations from data posted for Chicago at: https://data.cityofchicago.org/Public-Safety/Crimes-2001-to-present/ijzp-q8t2; for Los Angeles at: https://data.lacity.org/A-Safe-City/Crime-Data-from-2010-to-Present/y8tr-7khq; and New York at: https://data.cityofnewyork.us/Public-Safety/NYPD-Complaint-Data-Historic/qgea-i56i
- Weisburd, David, Elizabeth R. Groff, and Sue-Ming Yang. The criminology of place: Street segments and our understanding of the crime problem. Oxford University Press, 2012. ↩︎
- Sherman, Lawrence W., Patrick R. Gartin, and Michael E. Buerger. “Hot spots of predatory crime: Routine activities and the criminology of place.” Criminology 27, no. 1 (1989): 27-56. ↩︎
- MacDonald, John, George Mohler, and P. Jeffrey Brantingham. “Association between race, shooting hot spots, and the surge in gun violence during the COVID-19 pandemic in Philadelphia, New York and Los Angeles.” Preventive medicine 165 (2022): 107241. ↩︎
- Sampson, Robert J. Great American city: Chicago and the enduring neighborhood effect. University of Chicago Press, 2012. ↩︎
- Sampson, Robert J. 2011. “The Community.” Pp. 210-236 in Crime and Public Policy, edited by James Q. Wilson and Joan Petersilia. ↩︎
- Jacobs, Jane. 1961. The Death and Life of Greater American Cities. New York: Random House.; Clarke, Ronald V. 1995. “Situational Crime Prevention.” Crime and Justice 19: 91-150. ↩︎
- Jeffery, C. Ray. 1971. Crime Prevention Through Environmental Design. Beverly Hills: Sage Publications. ↩︎
- Branas, Charles C., Eugenia South, Michelle C. Kondo, Bernadette C. Hohl, Philippe Bourgois, Douglas J. Wiebe, and John M. MacDonald. “Citywide cluster randomized trial to restore blighted vacant land and its effects on violence, crime, and fear.” Proceedings of the National Academy of Sciences 115, no. 12 (2018): 2946-2951. ↩︎
- Wilson, James Q, and George L Kelling. 1982. “Broken Windows: The police and neighborhood safety.” The Atlantic, March. ↩︎
- Skogan, Wesley G. 1990. Disorder and Decline. New York: Free Press (p. 29). ↩︎
- MacDonald, John, Charles Branas, and Robert Stokes. Changing places: The science and art of new urban planning. Princeton University Press, 2019. (p. 3) ↩︎
- Cook, Philip J., and John MacDonald. “Public safety through private action: an economic assessment of BIDs.” The Economic Journal 121, no. 552 (2011): 445-462. ↩︎
- Chalfin, Aaron, Jacob Kaplan, and Michael LaForest. “Street light outages, public safety and crime attraction.” Journal of Quantitative Criminology 38, no. 4 (2022): 891-919. ↩︎
- Mitre-Becerril, David, Sarah Tahamont, Jason Lerner, and Aaron Chalfin. “Can deterrence persist? Long-term evidence from a randomized experiment in street lighting.” Criminology & public policy 21, no. 4 (2022): 865-891. ↩︎
- Welsh, Brandon C., and David P. Farrington. “Effects of improved street lighting on crime.” Campbell systematic reviews 4, no. 1 (2008): 1-51. ↩︎
- Sadatsafavi, Hessam, Naomi A. Sachs, Mardelle M. Shepley, Michelle C. Kondo, and Ruth A. Barankevich. “Vacant lot remediation and firearm violence–A meta-analysis and benefit-to-cost evaluation.” Landscape and Urban Planning 218 (2022): 104281. ↩︎
- Branas, Charles C., Eugenia South, Michelle C. Kondo, Bernadette C. Hohl, Philippe Bourgois, Douglas J. Wiebe, and John M. MacDonald. “Citywide cluster randomized trial to restore blighted vacant land and its effects on violence, crime, and fear.” Proceedings of the National Academy of Sciences 115, no. 12 (2018): 2946-2951.; Moyer, Ruth, John M. MacDonald, Greg Ridgeway, and Charles C. Branas. “Effect of remediating blighted vacant land on shootings: a citywide cluster randomized trial.” American journal of public health 109, no. 1 (2019): 140-144. ↩︎
- South, Eugenia C., John M. Macdonald, Vicky W. Tam, Greg Ridgeway, and Charles C. Branas. “Effect of abandoned housing interventions on gun violence, perceptions of safety, and substance use in Black neighborhoods: a citywide cluster randomized trial.” JAMA internal medicine 183, no. 1 (2023): 31-39.; MacDonald, John, Ahuva Jacobowitz, Jason Gravel, Mitchell Smith, Robert Stokes, Vicky Tam, Eugenia South, and Charles Branas. “Lessons learned from a citywide abandoned housing experiment.” Journal of the American Planning Association (2023): 1-14. ↩︎
- Braga, Anthony A., and Brenda J. Bond. “Policing crime and disorder hot spots: A randomized controlled trial.” Criminology 46, no. 3 (2008): 577-607. ↩︎
- Zhuo, Yilin, Emily Owens, and M. Keith Chen. Does neighborhood investment actually affect crime? New evidence from LIHTC and smartphone-based measures of policing. Technical report, 2023. ↩︎