Chicago’s predictive policing tool just failed a major test

Struggling to reduce its high murder rate, the city of Chicago has become an incubator for experimental policing techniques. Community policing, stop and frisk, "interruption" tactics — the city has tried many strategies. Perhaps most controversial and promising has been the city’s futuristic "heat list" — an algorithm-generated list identifying people most likely to be involved in a shooting.
The hope was that the list would allow police to provide social services to people in