By Maurice Chammah
The Marshall Project
Predicting crime has always been part of police work; any beat cop can tell you that a particularly dark street corner is vulnerable to carjackers, or a large parking lot offers anonymity for drug dealers. Scholars have been mapping crime since the 1800s, but during New York City’s crime spike in the 1990s, police officers started doing so systematically. Most notable among them was Jack Maple, a quick-talking, up-from-the-bottom transit cop who wore double-breasted suits, homburg hats, and two-tone shoes and has become a near-mythic figure in police circles. At the NYPD’s Manhattan headquarters, Maple would stretch out butcher paper across 55 feet of wall space. “I called them the Charts of the Future,” he once told an interviewer. “I mapped every train station in New York City and every train. Then I used crayons to mark every violent crime, robbery, and grand larceny that occurred.”
Maple’s boss, Police Commissioner Bill Bratton, sent officers to patrol the areas Maple marked up. The process evolved into an entire system of police management called CompStat, which uses data to hold individual precinct commanders accountable for the crime levels in their areas. In varying forms, “hot-spot policing” has spread throughout the nation’s police departments. Bratton calls it “computerized fishing.”
“Cops-on-dots,” as it’s sometimes known, has often been associated with Bratton’s other major legacy, “Broken Windows,” in which police target low-level offenses like graffiti and public drinking, creating a sense of public order that is believed to deter more serious crimes. Such tactics have been credited with helping bring down crime rates, but they have also contributed to the aggressive targeting — and stopping and searching — of black people, fostering resentment of police in many communities.
St. Louis officials had been using data to send police to patrol hot spots since 2009; today the city holds weekly meetings for commanders to discuss why certain crimes keep hitting certain places, and how to address it. When one precinct captain noticed a lot of robberies of appliances from houses under construction, officers were instructed to keep track of building schedules. In agencies across the country, the more commanders looked at the data, the more timely their responses to that data could be, and crime analysis started edging toward real time. The dream was to go beyond the present.
Picture: Youflavio (Own work) [CC BY-SA 4.0 (http://creativecommons.org/licenses/by-sa/4.0)%5D, via Wikimedia Commons