Proactive policing is a relatively new phenomenon in the United States. It developed from a crisis in confidence in policing that began to emerge in the 1960s because of social unrest, rising crime rates, and growing skepticism regarding the effectiveness of standard approaches to policing. In response, beginning in the 1980s and 1990s, innovative police practices and policies that took a more proactive approach began to develop. In this report, the committee used the term “proactive policing” to refer to all policing strategies that have as one of their goals the prevention or reduction of crime and disorder and that are not reactive in terms of focusing primarily on uncovering ongoing crime or on investigating or responding to crimes once they have occurred. Specifically, the elements of proactivity include an emphasis on prevention, mobilizing resources based on police initiative, and targeting the broader underlying forces at work that may be driving crime and disorder. This contrasts with the standard model of policing, which involves an emphasis on reacting to particular crime events after they have occurred, mobilizing resources based on requests coming from outside the police organization, and focusing on the particulars of a given criminal incident.
Proactive policing in this report is distinguished from the everyday decisions of police officers to be proactive in specific situations and instead refers to a strategic decision by police agencies to use proactive police responses in a programmatic way to reduce crime. This report has documented that proactive policing strategies are used widely in the United States. They are not isolated programs used by a select group of agencies but rather a set of approaches that have spread across the landscape of policing.
The United States has once again been confronted by a crisis of confidence in policing. Instances of perceived or actual police misconduct have given rise to nationwide protests against unfair and abusive police practices. Although this report was not intended to respond directly to the crisis of confidence in policing that can be seen in the United States today, it is nevertheless important to consider how proactive policing strategies may bear upon this crisis. It is not enough to simply identify “what works” for reducing crime and disorder; it is also critical to consider issues such as how proactive policing affects the legality of policing, the evaluation of the police in communities, potential abuses of police authority, and the equitable application of police services in the everyday lives of citizens.
Proactive policing has taken a number of different forms over the past two decades, and these variants often overlap in practice. The four broad approaches to proactive policing described in this report are place-based interventions, problem-solving interventions, person-focused interventions, and community-based interventions (see Table 2-1 in Chapter 2). Place-based interventions capitalize on the growing research base that shows that crime is concentrated at specific places within a city as a means of more efficiently allocating police resources to reduce crime. Its main applications have been directed at microgeographic hot spots. Person-based interventions also capitalize on the concentration of crimes to proactively prevent crime, but in this case it is concentration among a subset of offenders. Person-based interventions focus on high-rate criminals who have been identified as committing a large proportion of the crime in a community. Problem-solving innovations focus on specific problems that are viewed as contributing to crime incidence and that can be ameliorated by the police. In this case, a systematic approach to solve problems is used to prevent future crime. Finally, community-based interventions emphasize the role of the community in doing something about crime problems. Community approaches look to strengthen collective efficacy in the community or to strengthen the bonds between the police and the community, as a way of enhancing informal social controls and increasing cooperation with the police, with the goal of preventing crime.
In this concluding chapter, the committee summarizes the main findings for each of the four areas on which the report has focused: law and legality, crime control, community impacts, and racial disparities and racially biased behavior. For each area, we list the main conclusions reached (the conclusions are numbered according to the report chapter in which they were developed) and then provide a final, summary discussion of the findings. We then turn to the broader policy implications of the report as a whole. Finally, we offer suggestions for filling research gaps in order to strengthen the knowledge base regarding proactive policing and its impacts.
CONCLUSION 3-1 Factual findings from court proceedings, federal investigations into police departments, and ethnographic and theoretical arguments support the hypothesis that proactive strategies that use aggressive stops, searches, and arrests to deter criminal activity may decrease liberty and increase violations of the Fourth Amendment and Equal Protection Clause; proactive policing strategies may also affect the Fourth Amendment status of policing conduct. However, there is not enough direct empirical evidence on the relationship between particular policing strategies and constitutional violations to draw any conclusions about the likelihood that particular proactive strategies increase or decrease constitutional violations.
CONCLUSION 3-2 Even when proactive strategies do not violate or encourage constitutional violations, they may undermine legal values, such as privacy, equality, and accountability. Empirical studies to date have not assessed these implications.
However effective a policing practice may be in preventing crime, it is impermissible if it violates the law. The most important legal constraints on proactive policing are the Fourth Amendment to the U.S. Constitution, the Equal Protection Clause (of the Fourteenth Amendment), and related statutory provisions.
Although proactive policing strategies do not inherently violate the Fourth Amendment, any proactive strategy could lead to Fourth Amendment violations to the degree that it is implemented by having officers engage in stops, searches, and arrests that violate constitutional standards. This risk is especially relevant for stop, question, and frisk (SQF); broken windows policing; and hot spots policing interventions if they use an aggressive practice of searches and seizures to deter criminal activity.
In addition, in conjunction with existing Fourth Amendment doctrine, proactive policing strategies may limit the effective strength or scope of constitutional protection or reduce the availability of constitutional remedies. For example, when departments identify “high crime areas” pursuant to place-based proactive policing strategies, courts may allow stops by officers of individuals within those areas that are based on less individualized behavior than they would require without the “high crime” designation. In this way, geographically oriented proactive policing may lead otherwise identical citizen-police encounters to be treated differently under the law.
The Equal Protection Clause guarantees equal and impartial treatment of citizens by government actors. It governs all policies, decisions, and acts taken by police officers and departments, including those in furtherance
of proactive policing strategies. As a result, Equal Protection claims may arise with respect to any proactive policing strategy to the degree that it discriminates against individuals based on their race, religion, or national origin, among other characteristics. Since most policing policies today do not expressly target racial or ethnic groups, most Equal Protection challenges require proving discriminatory purpose in addition to discriminatory effect in order to establish a constitutional violation.
Specific proactive policing strategies such as SQF and “zero tolerance” versions of broken windows policing have been linked to violations of both the Fourth Amendment and the Equal Protection Clause by courts in private litigation and by the U.S. Department of Justice in its investigations of police departments. Ethnographic studies and theoretical arguments further support the idea that proactive strategies that use aggressive stops, searches, and arrests to deter criminal activity may decrease liberty and increase Fourth Amendment and Equal Protection violations. However, empirical evidence is insufficient—using the accepted standards of causality in social science—to support any conclusion about whether proactive policing strategies systematically promote or reduce constitutional violations. In order to establish a causal link, studies would ideally determine the incidence of problematic behavior by police under a proactive policy and compare that to the incidence of the same behavior in otherwise similar circumstances in which a proactive policy is not in place.
However, even when proactive strategies do not lead to constitutional violations, they may raise concerns about deeper legal values such as privacy, equality, autonomy, accountability, and transparency. Even procedural justice policing and community-oriented policing, neither of which are likely to violate legal constraints on policing (and, to the extent that procedural justice operates as intended, may make violations of law less likely), may, respectively, undermine the transparency about the status of police-citizen interactions and alter the structure of decision making and accountability in police organizations.
The available scientific evidence suggests that certain proactive policing strategies are successful in reducing crime and disorder. This important conclusion provides support for a growing interest among American police in innovating to develop effective crime prevention strategies. At the same time, there is substantial heterogeneity in the effectiveness of different proactive policing interventions in reducing crime and disorder. For some types of proactive policing, the evidence consistently points to effectiveness, but for others the evidence is inconclusive. Evidence in many cases is
restricted to localized crime prevention impacts, such as specific places, or to specific individuals. There is relatively little evidence-based knowledge about whether and to what extent the approaches examined in this report will have crime prevention benefits at the larger jurisdictional level (e.g., a city as a whole, or even large administrative areas such as precincts within a city) or across all offenders. One key problem that needs to be examined in this regard, but which has not been studied so far, is the degree to which specific policing programs create “opportunity costs” in terms of the allocation of police or policing resources in other domains. Furthermore, the crime prevention outcomes that are observed are mostly observed in the short term, and the evidence seldom addresses long-term crime-prevention outcomes.
It is important to note here that, in practice, police departments typically implement crime-reduction programs that include elements typical of several prevention strategies, as those strategies are defined for this report (see Chapter 2). Given this hybridization of tactics in practice, the committee’s review of the evidence was often hindered by the overlapping character of the real-world proactive policing interventions evaluated in many of the published research studies.
CONCLUSION 4-1 The available research evidence strongly suggests that hot spots policing strategies produce short-term crime-reduction effects without simply displacing crime into areas immediately surrounding targeted locations. Hot spots policing studies that do measure possible displacement effects tend to find that these programs generate a diffusion of crime-control benefits into immediately adjacent areas. There is an absence of evidence on the long-term impacts of hot spots policing strategies on crime and on possible jurisdictional outcomes.
CONCLUSION 4-2 At present, there are insufficient rigorous empirical studies on predictive policing to support a firm conclusion for or against either the efficacy of crime prediction software or the effectiveness of any associated police operational tactics. It also remains difficult to distinguish a predictive policing approach from hot spots policing at small geographic areas.
CONCLUSION 4-3 The results from studies examining the introduction of closed circuit television camera schemes are mixed, but they tend to show modest outcomes in terms of property crime reduction at high-crime places for passive monitoring approaches.
CONCLUSION 4-4 There are insufficient studies to draw conclusions regarding the impact of the proactive use of closed circuit television on crime and disorder reduction.
Policing has always had a geographic or place-based component, especially in how patrol resources are allocated for emergency response systems. However, over the past three decades scholars and the police have begun to recognize that crime is highly concentrated at specific places. Following this recognition, a series of place-based strategies have been developed in policing. In contrast to the focus of the standard model of policing, proactive place-based policing calls for a refocusing of policing on very small, “microgeographic” units of analysis, often termed “crime hot spots.” A number of rigorous evaluations of hot spots policing programs, including a series of randomized controlled trials, have been conducted.
The available research evidence suggests that hot spots policing interventions generate statistically significant short-term crime-reduction impacts without simply displacing crime into areas immediately surrounding the targeted locations. Instead, hot spots policing studies that do measure possible displacement effects tend to find that these programs generate a diffusion-of-crime-control benefit into immediately adjacent areas. While the evidence base is strong for the benefits of hot spots policing in ameliorating local crime problems, there are no rigorous field studies of whether and to what extent this strategy will have jurisdictionwide impacts.
Predictive policing also takes a place-based approach, but it focuses greater concern on predicting the future occurrence of crimes in time and place. It relies upon sophisticated computer algorithms to predict changing patterns of future crime, often promising to be able to identify the exact locations where crimes of specific types are likely to occur next. While this approach has potential to enhance place-based crime prevention approaches, there are at present insufficient rigorous empirical studies to draw any firm conclusions about either the efficacy of crime prediction software or the effectiveness of any associated police operational tactics. Moreover, it remains difficult to distinguish the police actions used in a predictive policing approach from hot spots policing at small geographic areas.
Another technology relevant to improving police capacity for proactive intervention at specific places is closed circuit television (CCTV), which can be used either passively or proactively. The results from studies examining the introduction of CCTV camera schemes are mixed, but they tend to show modest outcomes in terms of property crime reduction at high-crime places for passive monitoring approaches. Again, the committee did not find evidence that would allow us to estimate whether CCTV implemented as a jurisdictionwide strategy would have meaningful impacts on crime in that jurisdiction. As far as the proactive use of CCTV is concerned, there
are insufficient studies to draw conclusions regarding the impact of this strategy on crime and disorder.
CONCLUSION 4-5 There is a small group of rigorous studies of problem-oriented policing. Overall, these consistently show that problem-oriented policing programs lead to short-term reductions in crime. These studies do not address possible jurisdictional impacts of problem-oriented policing and generally do not assess the long-term impacts of these strategies on crime and disorder.
CONCLUSION 4-6 A small but rigorous body of evidence suggests that third party policing generates short-term reductions in crime and disorder; there is more limited evidence of long-term impacts. However, little is known about possible jurisdictional outcomes.
Problem-solving strategies such as problem-oriented policing and third party policing use an approach that seeks to identify causes of problems that engender crime incidents and draws upon innovative solutions to those problems to assess whether the solutions are effective. Problem-oriented policing uses a basic iterative process of problem identification, analysis, response, assessment, and adjustment of the response (often called the SARA [scanning, analysis, response, and assessment] model). This approach provides a framework for uncovering the complex mechanisms at play in crime problems and for developing tailored interventions to address the underlying conditions that cause crime problems in specific situations. Despite its popularity as a crime-prevention strategy, there are surprisingly few rigorous program evaluations of problem-oriented policing.
Much of the available evaluation evidence consists of non-experimental analyses that find strong associations between problem-oriented interventions and crime reduction. Program evaluations also suggest that it is difficult for police officers to fully implement problem-oriented policing. Many problem-oriented policing projects are characterized by weak problem analysis and a lack of non-enforcement responses to targeted problems. Nevertheless, even these limited applications of problem-oriented policing have been shown by rigorous evaluations to generate statistically significant short-term crime prevention impacts.
Third party policing draws upon the insights of problem solving, but also leverages “third parties” who are believed to offer significant new resources for preventing crime and disorder. Using civil ordinances and civil courts or the resources of private agencies, police departments engaged in third party policing recognize that much social control is exercised by
institutions other than the police (e.g., public housing agencies, property owners, parents, health and building inspectors, and business owners) and that crime can be managed through coordination with agencies and in ways other than enforcement responses under the criminal law. Though there are only a small number of program evaluations, the impact of third party policing interventions on crime and disorder has been assessed using randomized controlled trials and rigorous quasi-experimental designs. The available evidence suggests that third party policing generates statistically significant crime- and disorder-reduction effects. Related programs that employ Business Improvement Districts also show crime-prevention outcomes with long-term impacts, though research designs have been less rigorous in establishing causality.
CONCLUSION 4-7 Evaluations of focused deterrence programs show consistent crime control impacts in reducing gang violence, street crime driven by disorderly drug markets, and repeat individual offending. The available evaluation literature suggests both short-term and long-term areawide impacts of focused deterrence programs on crime.
CONCLUSION 4-8 Evidence regarding the crime-reduction impact of stop, question, and frisk when implemented as a general, citywide crime-control strategy is mixed.
CONCLUSION 4-9 Evaluations of focused uses of stop, question, and frisk (SQF) (combined with other self-initiated enforcement activities by officers), targeting places with violence or serious gun crimes and focusing on high-risk repeat offenders, consistently report short-term crime-reduction effects; jurisdictional impacts, when estimated, are modest. There is an absence of evidence on the long-term impacts of focused uses of SQF on crime.
In the standard model of policing, the primary goal of police was to identify and arrest offenders after crimes had been committed. But beginning in the early 1970s, research evidence began to suggest that the police could be more effective if they focused on a relatively small number of chronic offenders. These studies led to innovations in policing based on the logic that crime prevention outcomes could be enhanced by focusing policing efforts on the small number of offenders who account for a large proportion of crime.
Offender-focused deterrence strategies, also known as “pulling levers,” attempt to deter crime among a particular offending population and are
often implemented in combination with problem-solving tactics. Offender-focused deterrence allows police to increase the certainty, swiftness, and severity of punishment in innovative ways. These strategies seek to change offender behavior by understanding the underlying crime-producing dynamics and conditions that sustain recurring crime problems and by implementing a blended strategy of law enforcement, community mobilization, and social service actions.
A growing number of quasi-experimental evaluations suggest that focused deterrence programs generate statistically significant crime-reduction impacts. Robust crime-control impacts have been reported by controlled evaluations testing the effectiveness of focused deterrence programs in reducing gang violence and street crime driven by disorderly drug markets and by non-experimental studies that examine repeat individual offending. It is noteworthy that the size of the effects observed are large, though the committee observed that many of the largest impacts are in studies with evaluation designs that are less rigorous. The committee did not identify any randomized experiments in this program area. Nonetheless, many of the quasi-experiments have study designs that create highly credible equivalence between their treatment and comparison conditions, which supports interpreting their results as evidence of causation.
While SQF has long been a law enforcement tool of policing, the landmark 1968 Supreme Court decision Terry v. Ohio provided a set of standard criteria that facilitated its use as a strategy for crime control. According to that decision, police may stop a person based upon a “reasonable suspicion” that that person may commit or is in the process of committing a crime; if a separate “reasonable suspicion” that the person is armed exists, the police may conduct a frisk of the stopped individual. While this standard means that Terry stops could not be legally applied without reference to the behavior of the individual being stopped, interpretation of that behavior gave significant leeway to the police. As a proactive policing strategy, departments often employ SQF more expansively and to promote forward-looking, preventive ends.
Non-experimental analyses of SQF broadly applied across a jurisdiction show mixed findings. However, a separate body of controlled evaluation research (including randomized experiments) that examines the effectiveness of SQF and other self-initiated enforcement activities by officers in targeting places with serious gun crime problems and focusing on high-risk repeat offenders consistently reports statistically significant short-term crime reductions.
CONCLUSION 4-10 Existing studies do not identify a consistent crime-prevention benefit for community-oriented policing programs. However, many of these studies are characterized by weak evaluation designs.
CONCLUSION 4-11 At present, there are an insufficient number of rigorous empirical studies on procedural justice policing to draw a firm conclusion about its effectiveness in reducing crime and disorder.
CONCLUSION 4-12 Broken windows policing interventions that use aggressive tactics for increasing misdemeanor arrests to control disorder generate small to null impacts on crime.
CONCLUSION 4-13 Evaluations of broken windows interventions that use place-based, problem-solving practices to reduce social and physical disorder have reported consistent short-term crime-reduction impacts. There is an absence of evidence on the long-term impacts of these kinds of broken windows strategies on crime or on possible jurisdictional outcomes.
The committee also reviewed the crime-prevention impacts of interventions using a community-based crime prevention approach. Such strategies include community-oriented policing, broken windows policing, and procedural justice policing. The logic models informing these community-based strategies seek to enlist and mobilize people who are not police in the processes of policing. In this case, however, the focus is generally not on specific actors such as business or property owners (as in the case of third party policing) but on the community more generally. In some cases, community-based strategies rely on enhancing “collective efficacy,” which is a community’s ability to engage in collective action to do something about crime (e.g., community-oriented policing and broken windows policing). In other cases, community-based models seek to change community members’ evaluations of the legitimacy of police actions (e.g., procedural justice policing) with the goal of increasing cooperation between the police and the public or encouraging law-abiding behavior. These goals are often intertwined in a real-world policing program.
As a proactive crime-prevention strategy, community-oriented policing tries to address and mitigate community problems (crime or otherwise) and, in turn, to build social resilience, collective efficacy, and empowerment to strengthen the infrastructure for the coproduction of safety and crime prevention. Community-oriented policing involves three core processes
and structures: (1) citizen involvement in identifying and addressing public safety concerns; (2) the decentralization of decision making to develop responses to locally defined problems; and (3) problem solving. Problem solving and decentralization acquire a community-oriented policing character when these process elements are embedded in the community engagement (often called “partnership”) element.
Although the committee identified a large number of studies of community-oriented policing programs, many of these programs were implemented in tandem with tactics typical of other approaches, such as problem solving. This was not surprising, given that basic definitions of community policing used by police departments often included problem solving as a key programmatic element. The studies also varied in their outcomes, reflecting the broad range of tactics and practices that are included in community-oriented policing programs, and many of the studies were characterized by weak evaluation designs. With these caveats, the committee did not identify a consistent crime prevention benefit for community-oriented policing programs.
Procedural justice policing seeks to impress upon citizens and the wider community that the police exercise their authority in legitimate ways. When citizens accord legitimacy to police activity, according to this logic model, they are more inclined to defer to police authority in instances of citizen-police interaction and to collaborate with police in the future, even to the extent of being more inclined not to violate the law. There is currently only a very small evidence base from which to support conclusions about the impact of procedural justice policing on crime prevention. Existing research does not support a conclusion that procedural justice policing impacts crime or disorder outcomes. At the same time, because the evidence base is small, the committee also cannot conclude that such strategies are ineffective.
Broken windows policing shares with community-oriented policing a concern for community welfare and envisions a role for police in finding ways to strengthen community structures and processes that provide a degree of immunity from disorder and crime in neighborhoods. Unlike the community-oriented policing strategy, it does not emphasize the coproductive collaborations of police and community as a mode of intervention; rather, it focuses on what police should do to establish conditions that allow “natural” community entities to flourish and promote neighborhood order and social/economic vitality. Implementations of broken windows interventions vary from informal enforcement tactics (warnings, rousting disorderly people) to formal or more intrusive ones (arrests, citations, stop and frisk), all of which are intended either to disrupt the forces of disorder before they overwhelm a neighborhood’s capacity for order maintenance
or to restore afflicted neighborhoods to a level where intrinsic community sources of order can manage it.
The impacts of broken windows policing are mixed across evaluations, again complicating the ability of the committee to draw strong inferences. However, the available program evaluations suggest that aggressive, misdemeanor arrest–based approaches to control disorder generate small to null impacts on crime. In contrast, controlled evaluations of place-based approaches that use problem-solving interventions to reduce social and physical disorder provide evidence of consistent crime-reduction impacts.
There is broad recognition that a positive community relationship with the police has value in its own right, irrespective of any influence it may have on crime or disorder. Democratic theories assert that the police, as an arm of government, are to serve the community and should be accountable to it in ways that elicit public approval and consent. Given this premise and the recent conflicts between the police and the public, the committee thought it very important to assess the impacts of proactive policing on issues, such as fear of crime, collective efficacy, and community evaluation of police legitimacy.
CONCLUSION 5-1 Existing research suggests that place-based policing strategies rarely have negative short-term impacts on community outcomes. At the same time, such strategies rarely improve community perceptions of the police or other community outcome measures. There is a virtual absence of evidence on the long-term and jurisdiction-level impacts of place-based policing on community outcomes.
CONCLUSION 5-2 Studies show consistent small-to-moderate, positive impacts of problem-solving interventions on short-term community satisfaction with the police. There is little evidence available on the long-term and jurisdiction-level impacts of problem-solving strategies on community outcomes.
CONCLUSION 5-3 There is little consistency found in the impacts of problem-solving policing on perceived disorder, quality of life, fear of crime, and police legitimacy, except for the near-absence of backfire effects. The lack of backfire effects suggests that the risk is low of harmful community effects from tactics typical of problem-solving strategies.
CONCLUSION 5-4 Studies evaluating the impact of person-focused strategies on community outcomes have a number of design limitations that prevent causal inferences to be drawn about program effects. However, the studies of citizens’ personal experiences with person-focused strategies do show marked negative associations between exposure to stop, question, and frisk and proactive traffic enforcement approaches and community outcomes. The long-term and jurisdictionwide community consequences of person-focused proactive strategies remain untested.
Place-based, person-focused, and problem-solving interventions are distinct from community-based proactive strategies in that they do not directly seek to engage the public to enhance legitimacy evaluations and cooperation. In this context, the concerns regarding community outcomes for these approaches have often focused not on whether they improve community attitudes toward the police but rather on whether the focus on crime control leads inevitably to declines in positive community attitudes. Community-based strategies, in contrast, specifically seek to reduce fear, increase trust and willingness to intervene in community problems, and increase trust and confidence in the police.
A body of research evaluating the impact of place-based strategies on community attitudes is only now emerging; this research includes both quasi-experimental and experimental studies. However, the consistency of the findings suggests that place-based proactive policing strategies rarely have negative short-term impacts on community attitudes. At the same time, the evidence suggests that such strategies rarely improve community perceptions of the police or other community outcome measures. Moreover, existing studies have generally examined the broader community and not specific individuals who are the focus of place-based interventions at crime hot spots. As noted below, more aggressive policing tactics that are focused on individuals may have negative outcomes on those who have contact with the police. Existing studies also generally measure short-term changes, which may not be sensitive to communities that become the focus of long-term implementation of place-based policing. Finally, there has not been measurement of the impacts of place-based approaches on the broader community, extending beyond the specific focus of interventions.
The research literature on community impacts of problem-solving interventions is larger. Although much of the literature relies on quasi-experimental designs, a few well-implemented randomized experiments also provide information on community outcomes. Studies show consistent positive short-term impacts of problem-solving strategies on community satisfaction with the police. At the same time, however, the research base lacks estimates of larger jurisdictional impacts of these strategies.
Because problem-solving strategies are so often implemented in tandem with tactics typical of community-based policing (i.e., community engagement), it is difficult to determine what role the problem-solving aspect plays in community outcomes, compared to the impact of the community engagement element. Although this fact makes it difficult to draw strong conclusions about “what” is impacting community attitudes, as we note below, it may be that implementing multiple approaches in tandem can also have more positive outcomes for police agencies.
While there is evidence that problem-solving approaches increase community satisfaction with the police, we found little consistency in problem-solving policing’s impacts on perceived disorder/quality of life, fear of crime, and police legitimacy. However, the near-absence of backfire (i.e., undesired negative) effects in the evaluations of problem-solving strategies suggests that the risk of harmful community effects from problem-solving strategies is low. As with place-based approaches, community outcomes generally do not examine people who have direct contact with the police, and measurement of impacts is local as opposed to jurisdictional.
The body of research evaluating the impact of person-focused strategies on community outcomes is relatively small, even in comparison with the evidence base on problem-solving and place-based strategies; the long-term community consequences of person-focused proactive strategies also remain untested. These studies involve qualitative or correlational designs that make it difficult to draw causal inferences about typical impacts of these strategies. Correlational studies do find strong negative associations between exposure to the strategy and the attitudes and orientations of individuals who are the subjects of aggressive law enforcement interventions (SQF and proactive traffic enforcement). Moreover, a number of ethnographic and survey-based studies have found negative outcomes, especially for Black and other non-White youth who are continually exposed to SQFs. The studies that measure the impact on the larger community show a more complicated and unclear pattern of outcomes.
CONCLUSION 6-1 Community-oriented policing leads to modest improvements in the public’s view of policing and the police in the short term. (Very few studies of community-oriented policing have traced its long-term effects on community outcomes or its jurisdictionwide consequences.) These improvements occur with greatest consistency for measures of community satisfaction and less so for measures of perceived disorder, fear of crime, and police legitimacy. Evaluations of community-oriented policing rarely find “backfire” effects on community attitudes. Hence, the deployment of community-oriented policing
as a proactive strategy seems to offer prospects for modest gains at little risk of negative consequences.
CONCLUSION 6-2 Due to the small number of studies, mixed findings, and methodological limitations, no conclusion can be drawn about the impact of community-oriented policing on collective efficacy and citizen cooperative behavior.
CONCLUSION 6-3 The committee is not able to draw a conclusion regarding the impacts of broken windows policing on fear of crime or collective efficacy. This is due in part to the surprisingly small number of studies that examine the community outcomes of broken windows policing and in part to the mixed effects observed.
CONCLUSION 6-4 In general, studies show that perceptions of procedurally just treatment are strongly and positively associated with subjective evaluations of police legitimacy and cooperation with the police. However, the research base is currently insufficient to draw conclusions about whether procedurally just policing causally influences either perceived legitimacy or cooperation.
CONCLUSION 6-5 Although the application of procedural justice concepts to policing is relatively new, there are more extensive literatures on procedural justice in social psychology, in management, and with other legal authorities such as the courts. Those studies are often designed in ways that make causal inferences more compelling, and results in those areas suggest that the application of procedural justice concepts to policing has promise and that further studies are needed to examine the degree to which the success of such strategies in those other domains can be replicated in the domain of policing.
The available empirical research on community-oriented policing’s community effects focuses on citizen perceptions of police performance (in terms of what they do and the consequences for community disorder), satisfaction with police, and perceived police legitimacy. The evidence suggests that community-oriented policing leads to modest improvements in the community’s view of policing and the police in the short term. This occurs with greatest consistency for measures of community satisfaction and less so for measures of perceived disorder, fear of crime, and perceived legitimacy. Evaluations of community-oriented policing rarely find “backfire” effects from the intervention on community attitudes. Therefore, the deployment of community-oriented policing as a proactive strategy seems to offer prospects of modest gains at little risk of negative consequences.
Broken windows policing is often evaluated directly in terms of its short-term crime control impacts. We have emphasized in this report that the logic model for broken windows policing seeks to alter the community’s levels of fear and collective efficacy as a method of enhancing community social controls and reducing crime in the long run. While this is a key element of the broken windows policing model, the committee’s review of the evidence found that these outcomes have seldom been examined. The evidence was insufficient to draw any conclusions regarding the impact of broken windows policing on community social controls. Studies of the impacts of broken windows policing on fear of crime do not support the model’s claim that such programs will reduce levels of fear in the community, at least in the short run.
While there is a rapidly growing body of research on the community impacts of procedural justice policing, it is difficult to draw causal inferences from these studies. In general, the studies show that perceptions of procedurally just treatment are strongly correlated with subjective evaluations of police legitimacy. The extant research base on the impacts of procedural justice proactive policing strategies on perceived legitimacy and cooperation was insufficient for the committee to draw conclusions about whether procedurally just policing will improve community evaluations of police legitimacy or increase cooperation with the police.
Although this committee finding may appear at odds with a growing movement to encourage procedurally just behavior among the police, the committee thinks it is important to stress that a finding that there is insufficient evidence to support the expected outcomes of procedural justice policing is not the same as a finding that such outcomes do not exist. Moreover, although the application of procedural justice to policing is relatively new, there is a more extensive evidence base on procedural justice in social psychology and organizational management, as well as on procedural justice with other legal authorities such as the courts. Those studies are often designed in ways that make causal inferences more compelling, and results in those areas suggest meaningful impacts of procedural justice on the legitimacy of institutions and authorities involved. Thus, the application of procedural justice ideas to policing has promise, although further studies are needed to examine the degree to which the success of such implementations in other social contexts can be replicated in the arena of policing.
CONCLUSION 7-1 There are likely to be large racial disparities in the volume and nature of police–citizen encounters when police target high-risk people or high-risk places, as is common in many proactive policing programs.
CONCLUSION 7-2 Existing evidence does not establish conclusively whether, and to what extent, the racial disparities associated with concentrated person-focused and place-based enforcement are indicators of statistical prediction, racial animus, implicit bias, or other causes. However, the history of racial injustice in the United States, in particular in the area of criminal justice and policing, as well as ethnographic research that has identified disparate impacts of policing on non-White communities, makes the investigation of the causes of racial disparities a key research and policy concern.
Concerns about racial bias loom especially large in discussions of policing. The interest of this report was to assess whether and to what extent proactive policing affects racial disparities in police–citizen encounters and racial bias in police behavior. Recent high-profile incidents of police shootings and abusive police–citizen interaction caught on camera have raised questions regarding basic fairness, racial discrimination, and the excessive use of force of all forms against non-Whites, and especially Blacks, in the United States. In considering these incidents, the committee stresses that the origins of policing in the United States are intimately interwoven with the nation’s history of racial prejudice. Although in recent decades police have often made a strong effort to address racially biased behaviors, wide disparities remain in the extent to which non-White people and White people are stopped or arrested by police. Moreover, as our discussion of constitutional violations in Chapter 3 notes, the U.S. Department of Justice has identified continued racial disparities and biased behavior in policing in a number of major American police agencies.
As social norms have evolved to make overt expressions of bigotry less acceptable, psychologists have developed tools to measure more subtle factors underlying biased behavior. A series of studies suggest that negative racial attitudes may influence police behavior—although there is no direct research on proactive policing. There is a further growing body of research identifying how these psychological mechanisms may affect behavior and what types of situations, policies, or practices may exacerbate or ameliorate racially biased behaviors. In a number of studies, social psychologists have found that race may affect decision making, especially under situations where time is short and such decisions need to be made quickly. More broadly, social psychologists have identified dispositional (i.e., individual characteristics) and situational and environmental factors that are associated with higher levels of racially biased behavior.
Proactive strategies often facilitate increased officer contact with residents (particularly in high-crime areas), involve contacts that are often enforcement-oriented and uninvited, and may allow greater officer discretion compared to standard policing models. These elements align with
broad categories of possible risk factors for biased behavior by police officers. For example, when contacts involve stops or arrests, police may be put in situations where they have to “think fast” and react quickly. Social psychologists have argued that such situations may be particularly prone to the emergence of what they define as implicit biases.
Relative to the research on the impact of proactive policing policies on crime, there is very little field research exploring the potential role that racially biased behavior plays in proactive policing. There is even less research on the ways that race may shape police policy or color the consequences of police encounters with residents. These research gaps leave police departments and communities concerned with bias in police behavior without an evidence base from which to make informed decisions. Because of these gaps, the committee was unable to draw any concrete conclusions about the role of biased behavior in proactive policing. Consequently, research on these topics is urgently needed both so that the field may better understand potential negative consequences of proactive policing and so that communities and police departments may be better equipped to align police behaviors with values of equity and justice.
Inferring the role of racial animus, statistical prediction, or other dispositional and situational risk factors in contributing to observed racial disparities is a challenging question for research. Although focused policing approaches may reduce overall levels of police intrusion, we also detailed in Chapter 7 the very large disparities in the stops and arrests of non-White, and especially Black Americans, and we noted that concentrating enforcement efforts in high-crime areas and on highly active individual offenders may lead to racial disparities in police–citizen interactions. Although these disparities are often much reduced when taking into account population benchmarks such as official criminality, the committee also noted that studies that seek to benchmark citizen–police interactions against simple population counts or broad, publicly available measures of criminal activity do not yield conclusive information regarding the potential for racially biased behavior in proactive policing efforts. Identifying an appropriate benchmark would require detailed information on the geography and nature of the proactive strategy, as well as localized knowledge of the relative importance of the problem. Such benchmarks are not currently available. The absence of such benchmarks makes it difficult to distinguish between accurate statistical prediction and racial profiling.
Some of the most illuminating evidence on the potential impact of proactive policing and increased citizen–police contacts on racial outcomes relates to the use of SQF in New York City. This research seeks to model the probabilities that police suspicion of criminal possession of a weapon turns out to be justified, given the information available to officers when deciding whether to stop someone. This work finds substantial racial and
ethnic disparities in the distribution of these probabilities, suggesting that police in New York City apply lower thresholds of suspicion to blacks and Hispanics. We do not know whether this pattern exists in other settings.
Per the charge to the committee, this report reviewed a relatively narrow area of intersection between race and policing. This focus, though, is nested in a broader societal framework of possible disparities and biased behaviors across a whole array of social contexts. These can affect proactive policing in, for example, the distribution of crime in society and the extent of exposure of specific groups to police surveillance and enforcement. However, it was beyond the scope of this study to review them systematically in the context of the committee’s work.
In its review of the evidence, the committee tried to identify the most credible evidence on whether particular types of proactive policing strategies have been shown to affect legality, crime, communities, racial disparities, and racially biased behavior. A strategy is said to have “impact” if it affects outcomes compared with what they would have been at that same time and place in the absence of the implementation of a specific strategy. The strongest evidence often derives from randomized field trials and natural experiments in the field, typically implemented through a change in the activities of a police department structured so as to create a credibly comparable control condition with which to compare the “treatment” condition. However, as we have emphasized throughout the report, other methodological approaches can also provide rigorous evidence for the types of outcomes that we have examined. In turn, ethnographic studies have provided important information for the committee in understanding the processes that lead to such outcomes. Nonetheless, the emphasis in many sections of our report is on the “internal validity” of the evaluation: how strong is the evidence that a particular treatment implemented in a particular place caused the observed impact? And this assessment of validity has important implications for the strength of policy recommendations that we can draw from our review.
We want to emphasize that even a well-designed experimental trial implemented with fidelity may yield biased effect estimates if the outcomes data are not reliable. Most of the studies of crime outcomes examined in this report used crime data collected by the police department that is responsible for implementing the program. With the exception of homicide and perhaps motor-vehicle theft, the police only know of a fraction of all serious crimes. Less than one-half of robberies, aggravated assaults, and burglaries are reported to the police, and of course, reporting is a precondition for inclusion in the departmental statistics. That fact does not
negate the usefulness of these data in measuring impact, but it does compel consideration of whether the intervention is likely to affect the likelihood that a crime will be reported to and recorded by the police. For example, if a community-based policing intervention has the effects of both reducing crime and increasing the percentage of crimes reported to the police, the result might be that the latter will mask the former and obscure the crime-reduction effect. We note this possibility as a potential challenge to the internal validity of even well-designed and faithfully implemented experimental interventions, if they rely solely on police data.
Data that are collected by researchers may also have serious weaknesses. In some of the community surveys reviewed in this report, response rates were exceptionally low. A number of studies that we examined also used laboratory data; the laboratory environment allows a great deal of control over the research process but can be criticized as artificial and as a poor indicator of what actually happens in the field in policing.
More generally, we want to point to three specific limitations when it comes to the usefulness of this review in informing policy choice. First, the literature that we reviewed typically lacks much information on the magnitudes of the effects of the strategies evaluated. A clear demonstration that the “treatment effect” is greater than would be expected by chance—that is, that the estimated effect is statistically significantly different from zero—helps establish that the program “worked” but not that it was “worthwhile” from a policy perspective. A more complete evaluation would require a comparison of the estimated magnitude of the effect with an estimate of the costs of the program. How many serious crimes were prevented by the candidate program for every $100,000 worth of resources devoted to it, and what are the effects of removing that $100,000 from what it would otherwise have been used for? For a police chief or city mayor, resources are limited and must be accounted for in making well-informed choices about policing practice. This problem becomes even more difficult when one is trying to calculate costs and benefits for such outcomes as community satisfaction or perceived legitimacy. The literature rarely provides such a cost-effectiveness analysis, and hence this committee cannot provide policy proscriptions that would give specific advice about the costs or cost savings.
Second, and closely related, is that the evaluation evidence, because it typically does not account for cost, may actually provide a misleading impression of whether a program “worked”—whether in reducing crime or improving community attitudes for the entire jurisdiction—as opposed to having an effect only for the segment of the city represented by the treatment group. As we have noted throughout the report, most evaluations provide a local estimate of program impacts. They do not report how the program affected the jurisdiction overall. Absent such reports, or at least
evidence-grounded estimates of jurisdiction-level impact, it is very difficult to provide guidance to police executives about how redeployment of resources will impact overall trends across a city. Since most of the evaluations we reviewed assess local impacts only, we often do not know what the impacts of a program will be on the broader community when a program is broadly applied, as opposed to when it is implemented on a small scale.
Third, a police chief who is considering adopting a particular innovation may be able to make a prediction about whether it will reduce crime or improve community attitudes, based on evaluations of one or more similar programs, but that prediction must always be hedged by the constraint that making inferences about “here and now” based on “there and then” is a tricky business. A well-known example comes from the “coerced abstinence” program for drug-involved convicts known as HOPE. The program originated and was carefully evaluated in courts in Honolulu, Hawaii, where it appeared very effective. It has been replicated a number of times on the mainland United States, with at best mixed results. The variability in results may reflect differences in the quality of implementation by the law enforcement agencies, the modal type of drug of abuse (which differs among jurisdictions), or other factors.1 To the extent that programmatic effects are moderated by the characteristics of the target population and the implementing agency, then importing a program that appears promising into another setting can lead to disappointment. The uncertainties created by this “external validity” problem for evaluating field trials cannot be readily quantified. A common-sense view is that a single evaluation is not enough to establish a strong case for adoption in a different time and place and that understanding potential modifiers of the effects is important for evidence-based policy.
However, while acknowledging these caveats, the committee thinks that we can provide broad policy guidance regarding what the science of policing is today and how that might affect the choices that police executives make. Waiting until the evidence base is fully developed to draw from science in policy making is not only unrealistic—it also means that practitioners will not benefit from what is known already. Our report provides important knowledge for policing, knowledge that can help inform the debate about what the police should be doing. Nonetheless, as we have noted, there are important limitations in how existing knowledge can be used, and those limitations should be considered when drawing upon the science in this report.
A number of identifiable policing strategies provide evidence of consistent short-term crime-prevention benefits at the local level. These in-
1 For a discussion of HOPE, see the special issue of Criminology & Public Policy (November 2016), Volume 15, Issue 4.
clude hot spots policing, problem-oriented policing, third party policing, SQF targeted to violent and gun-crime hot spots, focused deterrence, and problem-solving efforts incorporated in broken windows policing. What these approaches have in common is their effort to more tightly specify and focus police activities. Police executives who implement such strategies are drawing upon evidence-based approaches. At the same time, the ability to generalize from existing evaluations to the broader array of at least larger American cities is sometimes limited by the limited number and scope of studies that are available, though in the case of hot spots policing a larger number of studies across diverse contexts have been carried out. We also find that these strategies, with the important exception of SQF, do not lead to negative community outcomes. With the caveats noted above, it appears that crime-prevention outcomes can be obtained without this type of unintended negative consequence. Albeit preliminary, this finding reinforces the policy relevance of these evidence-based approaches.
At the same time, the results of our review suggest that police executives should not view certain proactive policing approaches as evidence based, at least at this time. For instance, SQF indiscriminately focused across a jurisdiction or broken windows policing programs relying on a generalized approach to misdemeanor arrests (“zero tolerance”) have not shown evidence of effectiveness. This caveat, combined with research evidence that documents negative individual outcomes for people who are the subject of aggressive police enforcement efforts, even in the absence of clear causal interpretation, should lead police executives to exercise caution in adopting generalized, aggressive enforcement tactics. Moreover, our review of the constitutional basis for focusing police resources on people or places suggests that issues of legality are particularly relevant in the case of such strategies. Even in the case of focused programs for which there is evidence of crime-control success, when aggressive approaches such as SQF are employed, police executives must consider and actively try to prevent potential negative outcomes on the community and on legality, and they should cooperate with researchers attempting to quantify and evaluate these issues. This means not only that police executives should proceed with caution in adopting such strategies but also that agencies that are already applying them broadly and without careful focus should consider scaling down present efforts.
The committee’s findings regarding community-based strategies raise important questions about whether such approaches will yield crime-prevention benefits. Many scholars and policy makers have sought to argue that community-oriented policing and procedural justice policing will yield not only better relations with the public but also greater crime control. We do not find consistent evidence for this proposition, and police executives
should be accordingly wary of implementing community-based strategies primarily as a crime-control approach.
The committee also concluded that community-oriented policing programs were likely to improve evaluations of the police, albeit modestly. Accordingly, if the policy goal of an agency is to improve its relationship with the communities it serves, then community-oriented policing is a promising strategy choice, although we are unable to offer a judgment on whether the benefits are sufficient to justify the expected costs. Our review of policing programs with a community-based approach also suggests that police executives may want to consider applying multiple strategies as a more general agency approach. The difficulty of distinguishing the effects of community-based and problem-solving approaches that are often implemented together has been noted numerous times in this report. However, we also think that better outcomes may be obtained when programs are hybridized across the approaches defined in this report. If, for example, an agency seeks to improve both crime prevention and community satisfaction with the police, it seems reasonable to combine practices typical of community-oriented policing with evidence-based crime-prevention practices typical of strategies such as hot spots policing or problem-oriented policing. This has already been done in problem-solving approaches that emphasize community engagement, where these dual benefits have been observed.
Existing studies do not provide evidence of crime prevention effectiveness in the case of proactive procedural justice policing. Accordingly, the committee believes that caution should be used in advocating for such approaches on the ground that they will reduce crime. At the same time, studies reviewed by the committee did not find that procedural justice policing has the expected positive community outcomes. Does this mean that police should not encourage procedural justice policing programs? We think that this would be a serious mistake for two reasons. The first is simply that procedural justice reflects the behavior of police that is appropriate in a democratic society. Procedural justice encourages democratic policing even if it may not change citizen attitudes. The second reason relates to the state of research in this area. While it is a mistake to draw strong conclusions that procedural justice policing will improve community members’ evaluations of police legitimacy or cooperation with the police, it is equally wrong to draw the conclusion that it will not do so. Again, the evidence base here is too sparse to support either position.
While there is a large body of evaluation research in policing today, as contrasted with two or three decades ago, the committee identified a
number of key gaps in what is known about proactive policing. Filling such gaps in the evidence base is critical for developing the type of knowledge that, as we noted earlier, is necessary to inform policy decisions for policing. Policing in the United States represents a large commitment of public resources; it is estimated to cost federal, state, and local governments more than $125 billion per year (Kyckelhahn, 2015). Given that investment, the extent of the research gaps on proactive policing is surprising. For the police to take advantage of the revolution in police practices that proactive policing represents, they will need the help of the federal government and private foundations in answering a host of questions regarding effectiveness, community outcomes, legality, and racially biased behavior. The committee also noted an imbalance in the evidence base across the areas of the committee’s charge. While far from complete, there is a large body of credible causal evidence on the impact of proactive policing on crime rates. However, social science research of a similar form on other equally important outcomes of policing is only beginning to occur.
We think it also important to note at the outset that more research needs to be focused on the standard model of policing. The 2004 National Research Council report, Fairness and Effectiveness in Policing: The Evidence, argued that there was little evidence supporting such standard police practices as random police patrol across large areas, follow-up investigations, and rapid response to citizen calls for service. However, a number of new studies have been carried out since the 2004 study, and this recent research suggests that the view of the standard model of policing in that report may need to be reassessed (see, e.g., Chaflin and McCrary, 2017; Evans and Owens, 2007; Cook, 2015). In order to estimate the benefits of proactive policing efforts, more information is needed on whether standard policing practices are generating crime-prevention benefits, as well as sustaining and perhaps improving the community’s trust in and regard for the police.
Drawing conclusions about the efficacy of proactive policing strategies or about policing innovations more broadly is complicated by the absence of comprehensive data on police behavior in the field. Just because a policy has been formally adopted does not mean that officers on the beat behave according to the tenets of that policy. The impact of the adoption of a policy on any outcome is, essentially, a combination of the actual impact of a police agency adopting, for example, a place-based intervention, and the probability that officers actually implement this intervention as they engage in targeted patrol in particular places. Identifying ways to measure what police officers actually do is, therefore, a central problem for evaluat-
ing the impact of proactive policing strategies on crime, communities, and the legality of officer behavior.
To be useful for evaluating the impact of a proactive policing strategy on what officers do in the field, it is necessary for the data to, at minimum, measure officer behavior both before and after the policy change. Ideally, the data would span multiple agencies, thereby allowing for a more credible analysis of what officers might have done in the absence of the policy change. There have been some examples of efforts by governments to proactively develop such data sources. Such efforts include the Federal Bureau of Investigation’s National Use-of-Force Data Collection project, the Police Data Initiative in the Office of Community Oriented Policing Services (COPS Office) in the U.S. Department of Justice, and the proactive efforts in California to require local agencies to report information on all stops to that state’s Office of the Attorney General (CA AB 953).2 Similarly, there are a number of academic and nonprofit efforts to augment police data collection efforts and thereby provide enhanced analytic capacity, such as the Center for Policing Equity’s National Justice Database and the Stanford Open Policing Project.3 Substantially more effort needs to be devoted to collecting reliable data on how proactive policing is carried out in the field.4 Without the routine collection of such data, it is not possible to assess the prevalence and incidence of proactive policing or to characterize the content of such strategies.
The committee also noted more general weaknesses in existing studies that limit the conclusions that can be drawn. One important limitation is that proactive policing interventions often overlap in terms of the strategies represented by the elements of the intervention. For example, many place-based policing interventions include elements of a problem-solving approach, as do many community-based programs. While we recognize that the police and program developers are focused on crime prevention and not on identifying the specific components of a program that have impact, the mixing of elements from different approaches makes it extremely difficult to draw strong conclusions about which element(s) in a program had a crime-prevention impact. Therefore, it is very important in future research to develop study designs that allow identification of the specific mechanisms that produce impacts.
2 See https://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=201520160AB953 [November 2016].
4 Interesting new opportunities for such data collection have been taken advantage of by researchers. For example, S. Weisburd (2016) used GPS data on exactly where police cars are in Dallas, Texas, at small intervals of time to draw inferences about the effectiveness of police patrol in small areas.
More generally, it is important for evaluations to focus on the underlying logic models that are proposed to account for (or promise) program impacts. Broken windows policing, for example, was conceived as a method for increasing community social controls in the long run. However, very few studies of broken windows policing actually examine how police activities in reducing disorder will impact such long-term attitudes. This is true for many of the proactive policing strategies examined in this report. Research funding agencies should require the incorporation of tests of the validity of underlying logic models in their study solicitations.
The focus on short-run, rather than long-run, impacts also pervades the evaluation of crime incidence, which is the most researched outcome the committee examined. Seldom do researchers look at program impacts extending for more than a year after program initiation, and only a handful of the studies identified by the committee look at crime prevention in the long run. While research indicates that many proactive practices seem to create a crime-reduction effect in the short term, the long-term impacts of these programs also should be an important focus of study. And whereas most of the available research that measures community effects does so over a relatively short term (a year or less), it is likely that community effects—especially those involving people who have little or no direct contact with the police—require much longer to register. Some research suggests that community effects are dynamic, but that research has generally not examined effects over several years. For all these reasons, more research is needed that tracks the effects of proactive policing over several years.
With regard to the types of research conducted, more implementation and process evaluations are needed to better understand the challenges of getting programs and policies translated into police practice, as well as to better understand the actual practices that are being evaluated in terms of community outcomes. The standardization of measures of implementation and dosage for specific strategies will improve the capacity of systematic reviews of these studies to interpret an array of findings. In turn, in many areas there is a need for more rigorous evaluation designs—and especially the development of well-implemented randomized trials.
In looking at the studies reviewed in this report, the committee notes that most are concentrated in large, urban jurisdictions. Smaller, suburban, and rural jurisdictions are understudied, but they should be included in the mix of funded evaluations. Community dynamics in such jurisdictions may vary in ways not revealed in the studies of larger communities. Evaluations should also control for the larger organizational context in which policing programs operate. Little is known about how the structure of a department and, for example, its management style affects its ability to develop and sustain proactive policing programs that reduce crime while enhancing the legitimacy and legality of police officers’ actions. Further research is also
needed on how these outcomes are affected by police oversight and accountability mechanisms, including review boards, lawsuits, data disclosure requirements, and the standardized collection of data on officer activities (as recommended above).
Finally, the committee notes the absence of rigorous research on training of police. Training has been shown to change behavior in other settings, particularly management. Police training programs for proactive policing are recent, and there is very little evidence at this time about their long-term effects. Several recent studies suggest that training programs can influence officers’ attitudes toward, and behavior within, communities. Studies need to examine the impact of training on police officers’ orientations and behaviors. Expanding the Census of Law Enforcement Training Academies, and in particular identifying which agencies hire graduates, as opposed to simply how many agencies, is a possible first step that would facilitate linking officer training to actual field outcomes. It is especially important for future research to evaluate which training approaches and methods prove most effective for imparting the necessary will and skill required to implement a given proactive strategy well.
There is less research on how proactive policies influence the legality of officer behavior than on how those policies affect crime or community perceptions of crime. One of the hurdles is the absence of a clear measure of what, exactly, constitutes legal behavior on an officer’s part. Research on how to quantify the legality of police officer behavior in a way that is consistent with the law and lends itself to causal analysis is a necessary first step. Because of the complex issues involved, such research is likely to be most productive if conducted by members of the legal, social science, and police leadership communities in collaboration.
Researchers studying the impacts of proactive policies on citizen lawbreaking, using experimental or quasi-experimental designs and administrative data, also should identify the relevant legal standards for officer behavior and include measures of officer behavior that are affected by these standards as one of their assessed outcomes. Ethnographic, qualitative, and mixed methods social science research, as well as legal scholarship, should inform how quantitative researchers conceptualize these measures. Given that officer law-breaking is as important, if not more so, in a general evaluation of such policies as undesirable behavior on the part of citizens, researchers who have access to administrative data that measure and make reliable legal judgments about officer behavior, including data collected by body-worn cameras, should include assessment of such outcomes in their analysis of the policies’ impacts on crime by citizens.
As noted above, while the committee has provided a series of conclusions regarding the crime- and disorder-control impacts of proactive policing, there are significant caveats that limited our ability to develop specific policy prescriptions. Given the importance of the policing enterprise and its impacts on U.S. society, we think that a major investment in research on proactive policing is warranted, with a complementary investment in assessing standard policing practices.
A better understanding is needed of the crime-prevention effects of proactive policing programs relative to each other and relative to such activities as crime investigation, response to 911 calls, and routine patrol. For example, which types of proactive activities create a greater deterrent effect in a crime hot spot: foot patrol, technological surveillance (such as CCTVs), problem-solving projects, enforcement activities, or situational crime-prevention strategies? Can gun crimes be best reduced through focused deterrence/pulling levers, pedestrian and traffic stops, or crime prevention through environmental design?
Equally important to the relative deterrent effect of proactive policing approaches are the social costs and collateral consequences of those approaches. At the most basic level, identifying other effects than crime reduction of proactive policing approaches—positive or negative—is needed. Once identified, measuring for these effects when testing for the crime prevention effects of proactive policing should be included in study designs.
A key issue in place-based studies is whether crime displaces to other areas. There is now a strong literature showing that immediate geographic displacement is not common, and studies instead point to a diffusion of crime control benefits to areas near targeted hot spots. However, little is known about displacement to more distal areas and whether such displacement affects the crime prevention benefits of place-based strategies. Study of distal displacement needs to be a central feature of the next generation of research on place-based policing. Most evaluations also provide only local estimates of impacts, and it is critical to examine whether place-based strategies implemented across cities will have jurisdictional impacts. Estimating the size of jurisdictional impacts for strategies such as hot spots policing is critical for police executives and policy makers as they consider the wider benefits of these approaches.
More research is also needed on how technology contributes to the crime prevention effects of proactive policing strategies. There has been relatively little research on the impacts of technology in policing beyond technical, efficiency, or process evaluations. More studies of the crime-control impacts of license plate readers, body-worn cameras, gun-shot detection technologies, forensic technologies, and CCTV are needed. Furthermore,
the effectiveness of analytic technologies such as crime analysis and predictive policing software applications also remains under-researched. Given their increased use in proactive policing strategies, much more needs to be known.
To date, there are no rigorous outcome evaluations of law enforcement proactive interventions designed to reduce and prevent technology-related crime, such as cybercrime, fraud and theft using the Internet, or hacking. Proactive activities by federal agencies such as the Federal Bureau of Investigation or the U.S. Department of Homeland Security remain completely immune from public-domain evaluation in this and all other aspects of their proactive efforts.
Finally, it is important to determine whether community-oriented or procedural justice approaches can produce crime prevention effects. While improving citizen reaction to police activity is an important goal in and of itself, equally important—and connected to this goal—is the detection, prevention, reduction, and control of crime. Perhaps community-oriented or procedural justice approaches can be combined with other effective practices from the place-based, person-focused, or problem-solving approaches to attain both goals. But to date, the effectiveness of community-oriented and procedural justice interventions in crime control is uncertain.
While there is broad recognition of the importance of community impacts of proactive policing strategies, there are only a few studies available on the community impacts of place-based and person-focused strategies, and the results for most types of outcomes are varied. A more extensive menu of observational, quasi-experimental, and experimental evaluations is needed. Systematic assessment of the contingent nature of outcomes is needed. Moreover, although a variety of logic models propose to account for the role that various community outcomes play in the process of affecting crime and disorder levels and community perceptions and behaviors, these logic models have not been subjected to rigorous empirical tests.
A gap noted throughout the research on community impacts is the lack of studies of the long-term effects of proactive strategies. Regardless of the rigor of the evaluation design in terms of inferring causal linkages between strategies and community outcomes, the extant literature provides only an ahistorical, incomplete, and potentially misleading perspective on what the consequences of proactive strategies will be. Future research should take into account both the long-term exposure of research subjects to proactive policing and the need to track the community consequences of those strategies over years, not months. Both variation in the accumulation of dosage over extended time and the consequences of this extended exposure are
virtually unexplored. Whether and how much a pattern of consequences is sustained or decays is also important to know.
One approach to changing community perception of police legitimacy is to change police behavior during contacts with the public. There is considerable evidence in the social psychology literature suggesting that personal contacts can change attitudes. However, there is insufficient research on the likelihood that one personal contact with a police officer can change orientations that have built up over a lifetime, irrespective of how the police behave during that single contact. Studies of the impact of a single experience with the police on a person’s general orientation toward the police are relatively few, and the results are mixed. Research is needed that tests the ability of a single interaction to shape general views about police legitimacy. This work needs to consider different types of encounters. It also needs to take account of characteristics of the person being stopped (race, age, gender, trust in the police) and that person’s history of encounters with the police. Finally, there needs to be a broader consideration of impacts on communities and the inevitable interactions between what the police do in a community and how that activity affects the development trajectory of that community, not only with respect to crime but also for housing, economic development, and other social outcomes.
The committee believes that the area of racial disparity and racially biased behavior is a particularly important one for enhancing the rigor and quantity of research on proactive policing. The committee identified five areas where research is most urgently needed with regard to racially biased behavior and proactive policing: (1) psychological risk factors, (2) training on bias reduction, (3) attention to behavioral bias as an important outcome of research on crime reduction, (4) an emphasis on assessing “downstream” consequences of proactive policing on racial outcomes, and (5) an emphasis on “upstream” influences regarding how proactive policing approaches are adopted.
First, a focus is needed on the psychological mechanisms of racially biased police behavior in actual field contexts, not only in laboratory simulations. As we reviewed in Chapter 7, research in social psychology has identified a number of risk and protective factors that in laboratory settings are associated with either an increase or decrease in racially biased behaviors, even in subjects who do not appear to harbor racial animus. Many situations common in proactive policing map onto these factors. In spite of the potential relevance of the laboratory findings, there is virtually no evidence about whether or not police contexts or trainings produce sufficient protections against those risks in the field. A systematic approach to
these risk factors in proactive policing would be an important step toward producing an evidence base for evaluating racial disparities in proactive policing.
Second, rigorous research is needed on whether police training in this area affects actual police behavior. Even though there have been large investments in police training to address racial bias and disparate treatment, there are at present no rigorous studies that inform these efforts.
Third, the incidence of racially biased behavior and of racial disparities in outcomes should become an important outcome metric for research on proactive policing. To date, outcome evaluations in policing have focused primarily on crime control and at times on community satisfaction or perceived legitimacy. Seldom have studies assessed racial outcomes of proactive policing, despite the fact that these outcomes constitute a key issue for policy in American society. Assessing disparate impacts in policing in an informative way will require spatially detailed demographic information about the population at risk of encountering the police when the policy is in place, in order to identify an appropriate benchmark and identify the marginal person affected by the policy. Until standardized metrics for measuring racially biased behavior are available, along with measures of the populations exposed to proactive policing policies, thorough assessments of proactive policing efforts will likely require formal empirical analysis, as well as qualitative and ethnographic analysis, of proactive strategies, their implementation, and their impacts.
Fourth, understanding the downstream consequences of racial disparities is an urgent research need. Does proactive policing have a long-term impact on racial disparities or race relations in communities? What are the costs of such impacts, and can and should they be compared to the crime-control benefits of proactive policing? As we argued in Chapter 7, proactive policing may lead to long-term decreases in inequalities in communities because of the benefits of lowered crime and related social consequences of crime. But little is known about such issues to date. To weigh these potential costs of proactive policing against the crime-reducing benefits, researchers must develop some metric for quantifying and estimating the cost of racial disparities, racially biased behavior, and racial animus. Survey techniques commonly used for cost-benefit research in environmental economics may be a useful guide.
Finally, the committee identified very little research on what drives law enforcement agencies to adopt proactive police policies. The history of criminal justice and law enforcement in the United States, along with ethnographic evidence on how police actions are perceived in communities, suggests that the role of race and ethnicity in the adoption of policing practices should be carefully assessed. However, scholars of proactive policing have yet to study carefully how race may influence the adoption of specific
proactive policing policies. It is critically important to understand not only the impacts of proactive policing on racial outcomes but also how race may affect the adoption of specific types of proactive policing. This was a concern raised to us by representatives of such groups as The Movement for Black Lives and the NAACP Legal Defense and Educational Fund (see Chapter 7 and Appendix A). Are more aggressive proactive policing strategies more likely to be chosen when Black or disadvantaged communities are the focus of police enforcement? This question needs to be addressed systematically in future research.
Proactive policing has become a key part of police efforts to do something about crime in the United States. This report supports the general conclusion that there is sufficient scientific evidence to support the adoption of some proactive policing practices. Proactive policing efforts that focus on high concentrations of crimes at places or among the high-rate subset of offenders, as well as practices that seek to solve specific crime-fostering problems, show consistent evidence of effectiveness without evidence of negative community outcomes. Community-based strategies have also begun to show evidence of improving the relations between the police and public. At the same time, there are significant gaps in the knowledge base that do not allow one to identify with reasonable confidence the long-term effects of proactive policing. For example, existing research provides little guidance as to whether police programs to enhance procedural justice will improve community perceptions of police legitimacy or community cooperation with the police.
Much has been learned over the past two decades about proactive policing programs. But now that scientific support for these approaches has accumulated, it is time for greater investment in understanding what is cost-effective, how such strategies can be maximized to improve the relationships between the police and the public, and how they can be applied in ways that do not lead to violations of the law by the police.