Cambridge hearing exposes split over police use of ShotSpotter (Sound Thinking)

The Cambridge Public Safety Committee on May 21 held a public hearing to review the Cambridge Police Department’s 11‑year use of ShotSpotter gun‑detection technology, now branded Sound Thinking, bringing sharply divergent views on whether the system improves response times or creates unacceptable surveillance risks.

The hearing featured presentations by Cambridge police officials and a company representative, followed by an academic critic and technical expert. Police and the district attorney described examples in which alerts preceded 911 calls and assisted rapid responses; researchers and public defenders questioned the company’s claims, the completeness of the data and whether recordings or retained data could be shared beyond the city.

Cambridge Police Commissioner Christine Elo said the department views ShotSpotter as a tool, not “a fix all,” and described cases in which alerts arrived before 911 calls and officers reached victims or recovered evidence faster than they otherwise would have. Acting public information officer Bob Reardon briefed the committee on the system’s local footprint: Cambridge’s ShotSpotter coverage is about 1.255 square miles and has been funded by the Urban Areas Security Initiative (UASI); he told the committee the city’s UASI grant covers a roughly $50,000 annual contract cost.

The department presented its recent incident counts and system performance for committee members. CPD slides summarized 2023 as having six confirmed shootings citywide (all inside the ShotSpotter coverage area), with four incidents identified by…