Three weeks into his new job as commanding officer of Manhattan’s 20th precinct, Captain Timothy J. Malin stared at a map on his computer screen, puzzled. It showed his jurisdiction carved up by streets and parks, with the southern edge encased in an ominous shade of red. For decades, the New York Police Department has used real-time statistics to chart spikes in violence and calibrate police activity across the city.

Learn about your ad choices: dovetail.prx.org/ad-choices