ShotSpotter

CTL-E-6376 · Technology · 2012–2024

VERIFIED evidence grade — build store (JSON graph)

Combined Graph record U-07562 · provenance: build store (JSON graph), record CTL-E-6376.

ShotSpotter is a gunshot-detection system made by SoundThinking, Inc., formerly ShotSpotter, Inc. Acoustic sensors placed across a coverage area detect loud impulsive sounds; an algorithm filters them and a trained human reviewer confirms gunfire before police are notified, a process the company says takes under 60 seconds. Chicago first installed it in about three square miles in September 2012, expanding to 136 square miles by May 2018, according to Vital City. The city's Office of Inspector General reported in 2021 that responses to alerts rarely produced evidence of a gun-related crime. Mayor Brandon Johnson announced the contract would not be renewed, and it lapsed September 22, 2024. In August 2025 the city settled a lawsuit conceding alerts alone do not justify stops. Chicago voters face a November 2026 advisory question on restarting gunshot detection.

The record

• Also known as: SoundThinking ShotSpotter

Notes

TYPING CALL: the backlog proposed Product/Topic; the schema has neither — Technology is the legal home (precedent: the live SAP Fieldglass record). No subtype: the schema defines no Technology subtype list. ERA: September 2012 – 22 September 2024 is the Chicago deployment, this record's frame; the system continues elsewhere (out of scope). GRADE BASIS: Verified, with two caveats stated plainly — (1) the 2021 OIG ShotSpotter report itself was not fetched directly; its finding reaches this record through independent summaries (Reason's summary gives the underlying figure: 9.1% — 4,556 of 41,830 dispositions with evidence of a gun-related offence, January 2020–May 2021); (2) the $90,000 settlement figure rests on the Sun-Times republication only and is excluded from the description. CONFLICT SHOWN, NOT BLENDED: coverage 136 sq mi (Vital City, by May 2018) vs 117 sq mi (OIG-report summary, 2021 context). BLOCKED EDGES: created_by → SoundThinking, Inc. (vendor not homed); any 'used by' edge to the Chicago Police Department (CTL-E-1846) — Technology's only outgoing predicates are created_by and succeeded_by, CPD did not create the system, and the schema has no used_by predicate; EB-32 ↔ EB-33 kinship (both CPD data systems contested on racial-disparity grounds, each sourced to OIG reports) has no legal predicate either. PHOTO: HELD (see media). CURATOR'S JUDGMENT (DRAFT): ShotSpotter is where the New Jim Code met a Chicago budget line — the record belongs in the graph because the argument was settled here, in public, with an Inspector General's report and a settlement. (Draft judgment, not fact.)

Sources

• “ShotSpotter uses acoustic sensors throughout a coverage area that work 24×7 to detect loud, impulsive sounds… a trained human reviewer analyzes the sound… Only then does ShotSpotter notify police… less than 60 seconds.” Accessed 2026-10-29. (primary source · build store)
• “Chicago initially installed ShotSpotter in September 2012 within an approximately three-square-mile area, with coverage expanding to 136 square miles by May 2018.” Accessed 2026-10-29. (build store)
• “In August 2025, the City agreed to settle a class-action lawsuit… with the City conceding that alerts alone do not justify police stops… required that if the City ever returns to a contract with ShotSpotter, they must adopt a police directive acknowledging that a ShotSpotter alert does not count as reasonable suspicion.” Accessed 2026-10-29. (build store)
• Chicago residents “are being asked to vote on three advisory referenda, one of which gauges opinion on whether the city should restart the use of a gunshot detection system… after Mayor Brandon Johnson discontinued the use of ShotSpotter.” Accessed 2026-10-29. (build store)

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Researched and maintained by the CultureTechLens research program · CultureTechLens Combined Graph, Release 2026-11-04. Corrections are public: the corrections log.

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