Almost a quarter-billion calls are placed to 911 each year in the United States. A large share of them involve social problems, not crimes or emergencies—yet police are dispatched in response. This review traces how the 911 emergency system’s institutional design shapes demand for police, who is excluded from or ill served by this system, and what alternatives exist, including nonemergency lines (with police response), government hotlines (211, 311, 988), civilian crisis teams, and community-based resources. Among the universe of municipal police departments with at least 100 sworn officers in 2020, covering 107 million US residents, police have absorbed broad social service functions, with the availability of formal alternatives restricted to the largest cities. The evidence suggests that the primacy of police reflects institutional reproduction more than public need. I propose priorities for future research.

That is from a new NBER working paper by Bocar A. Ba.