Police are the members of the criminal justice system who are most immediately involved in reducing crime. In 1999 there were an estimated 13,524 local police departments in the United States, employing about 436,000 full-time sworn officers. The strategies that police employ in fighting crime vary from city to city and even from department to department. Since the early 1990s, however, community policing has emerged as one of the most popular concepts in crime control.

In broad terms, “community policing” simply refers to the practice of police working with the community to reduce crime. The National Institute of Justice report Preventing Crime: What Works, What Doesn’t, What’s Promising highlights several common characteristics of community policing initiatives. The first is neighborhood watch programs, in which neighbors volunteer to monitor streets for criminal activity. The second is intelligence sharing: Through increased...