Evidence on what makes police effective points to the vital role of crime analysis in 21st century policing. Understanding this research can help you apply the lessons the police profession has learned over the last third of a century.

There has been considerable research into which police practices are effective at reducing crime and which practices are not effective. Recently, the National Academy of Sciences established a panel of social science experts to review all police research including the question of police effectiveness. The figure is adapted from this report. The least effective approaches to crime reduction are in the lower left quadrant and the most effective are in the upper right.

In the lower left corner of the figure, we have the "standard model" of policing. This is the dominant policing strategy in North America. The standard model is characterized by its reliance on law enforcement and a lack of focus. Here we find general patrolling to deter offenders, rapid responses to a wide variety of calls for police service, follow-up investigations of crimes, and other law enforcement activities that make little distinction among the characteristics of the people, places, times, or situations. Faced with a public demand to reduce crime, public officials and the press who are wedded to the standard model will request more police officers, decreases in response time, greater police visibility, higher success rates in investigations, and more arrests. Equally important is what the press and public officials do not call for - increased precision as to who, what, when, where, why, and how crimes take place, distinctions among crime types, the involvement of other public and private institutions to address crime, or the application of non-law enforcement alternatives.

Some of the earliest research into police effectiveness addressed aspects of the standard model. This research has consistently failed to find that the standard model has any noticeable effect on crime, disorder, or fear of crime. Random patrol, rapid response, follow-up investigations, and arrest policies may be very beneficial for other purposes, but we should not expect any of these practices to have an impact on crime or disorder. Nor is there solid evidence that adding police to carry out these practices will affect crime.

To have an effect on crime, research strongly suggests that police strategies must include two elements. These are represented on the axes of the figure. First, the strategy must diversify its approaches to crime and disorder. That is, policing must address crime and disorder using a greater range of tools than simply enforcing the law. This idea is expressed on the vertical axis. There is evidence that working with the public, and going beyond law enforcement, can have modest crime and disorder reduction effects, and the more personal the police-citizen contacts the more likely it is that they will have an effect on crime.

The second element necessary to highly effective policing is focus. This element is expressed in the horizontal axis of the figure. There is generally solid evidence that geographically concentrated enforcement at crime or disorder hot spots can be effective, at least in the short run. That is, focused patrolling of very small high-crime places (e.g., street corners and block faces) has a modest effect on crime and a large effect on disorder. This can be accomplished with or without intensive arrest actions. CompStat and other related innovations of the late 1990s seek to take advantage of these findings. The Office of Community Oriented Policing Services has published a Problem-Oriented Guide about when crackdowns and related tactics are and are not effective (see Read More).

If a few individuals are responsible for most crime or disorder, then removing them should reduce crime. Though sound in principle, the research testing this idea is very poor so we do not know whether repeat offender programs work in actual practice, or if they are a seemingly promising notion that cannot effectively be carried out.

Problem-oriented policing applies both elements combining the use of diverse approaches with focused action. How effective is it? There is a large body of evaluation evidence here applying weak-to-strong research methods that consistently finds that this combination does reduce crime and disorder. First, many problem-solving efforts have been applied after concentrated enforcement has failed to produce long lasting effects on crime, so something else needs to be done. In one of the earliest examples, police in Newport News, Virginia, had been struggling with the exceptionally high burglary rate in the New Briarfield apartments for well over a decade. They had obtained some short-term results from various enforcement methods, such as foot patrols and mini-station programs. But each time the police redeployed away from New Briarfield the burglary rate surged. It was only after applying a problem-oriented approach - involving citizens, the public housing authority, the fire department, the city codes department, and the U.S. Department of Housing and Urban Development - that they were able to substantially reduce burglaries. Second, when problem-solving at drug hot spots was compared to traditional law enforcement at drug hot spots in a Jersey City, New Jersey, randomized experiment, David Weisburd and Lorraine Green found that problemsolving had the greater impact. So, even though focused law enforcement is more effective than unfocused law enforcement, focused problem-solving is even more effective.

The lessons during a third of a century of research are now clear. Effective police work requires both focused attention and diverse approaches. The least effective policing uses neither element. The explanation for this is also clear. If diverse approaches are used without focus, it is difficult to apply the appropriate approach to the places and people who most require it. If police are focused on hot spots, but only enforce the law, they limit their effectiveness. A fully effective police agency must take advantage of the details of crime situations to reduce crime opportunities. Crime analysts have important roles in applying both elements - focusing with precision using their analytical methods, and helping to craft appropriate police tactics that fit the details of problems they have uncovered. This makes the 21st century the century of crime analysis in policing.

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Effectiveness of Policing Strategies

Adapted from National Research Council (2003), Fairness and Effectiveness in Policing: The Evidence. Committee to Review Research on Police Policy and Practice. Edited by Wesley Skogan and Kathleen Frydl. Washington, DC: The National Academies Press. Figure 6.1 and Table 6.1, pp. 248-249.