What is the aim of this review?

This Campbell systematic review examines the effects of disorder policing interventions on crime. The review summarises evidence from 28 high-quality studies (representing 30 independent tests), including nine randomised controlled trials. Most the studies come from the USA.

What is this review about?

Policing social and physical disorderly conditions is rooted in the broken windows approach: disorder is a precursor to more serious crime, fear of crime, and neighborhood decline. Addressing disorder has become a central fixture of policing, especially in the USA. Yet, evaluations of the effectiveness of disorder policing strategies in controlling crime yield conflicting results.

Policing disorderly conditions can be divided into two main strategies: (1) Order maintenance or zero tolerance policing, where police attempt to impose order through strict enforcement; and (2) Community policing and problem-solving policing, where police attempt to produce order and reduce crime through cooperation with community members and by addressing specific recurring problems.

This review examined the effects of disorder policing strategies compared to traditional law enforcement actions (e.g., regular levels of patrol) on the rates of crime, including property crime, violent crime, and disorder/drug crime. This review also examined whether policing disorder actions at specific locations result in crime displacement (i.e., crime moving around the corner) or diffusion of crime control benefits (i.e., crime reduction in surrounding areas).

What studies are included?

A total of 28 disorder policing studies (representing 30 independent tests) met the criteria to be included in this review. The studies spanned the period from 1985 to 2012, and were mostly carried out in the USA. All of the studies used high-quality designs to evaluate the impact of the intervention; nine were randomised controlled trials. Twelve tests were completed in large cities (more than 500,000 residents), nine tests were completed in medium-sized cities (200,000 to 500,000 residents), and the other nine tests were completed in smaller cities. All of the tests were carried out in specific geographical settings, including small places (e.g., crime hot spots and problem buildings), smaller police-defined areas (e.g., patrol beats), neighbourhoods and selected stretches of highways, and larger police-defined areas (e.g., precincts and divisions).

What are the main findings of this review?

• Do policing interventions focused on disorderly conditions reduce crime?

Yes, in addition to an overall reduction in crime, there is a reduction in property crime, violent crime, and disorder/drug crime when disorder policing interventions are implemented.

• Do policing interventions focused on disorder result in crime being displaced or crime control benefits being diffused to surrounding areas?

Disorder policing interventions are associated with diffusion of crime control benefits in areas surrounding targeted locations. This conclusion is based on 15 tests that measured displacement or diffusion effects.

• Of the two main strategies used in policing disorder, is one more effective than the other?

Yes, policing disorder through community and problem-solving is associated with reductions in crime. Aggressive, order maintenance approaches are not effective.

What do the findings of the review mean?

The types of strategies used by police departments to address disorderly conditions seem to matter in controlling crime, and this holds important implications for police-community relations, justice, and crime prevention. Further research is needed to understand the key programmatic elements that maximise the capacity of these strategies