"Most relevant measures of police activity did not change abruptly enough to explain the surge in gun violence. Overall arrests declined in 2016, driven by narcotics arrests, but arrests for violent crimes, including homicides and shootings, barely changed. One policing measure that declined was the chance of arrest for homicides and shootings (the 'clearance rate'), which was a result of arrests for these crimes not keeping pace with the increase in gun violence. Another policing measure that declined was the number of investigatory street stops. However, for this to explain why shootings increased in Chicago would also require an explanation for why the previous dramatic decline in street stops in New York City did not lead to more gun violence there."