{
  "id": "R-3573",
  "title": "ShotSpotter gunshot alerts used to justify investigatory stops and frisks, Chicago Police Department, Chicago, 2018–2021",
  "short_title": "ShotSpotter alerts used to justify stops and frisks",
  "jurisdiction": {
    "country": "United States",
    "region": "Chicago, Illinois",
    "level": "municipal"
  },
  "domain": "policing",
  "system_type": "ml_classifier",
  "system_name": "ShotSpotter",
  "deployed_by": "Chicago Police Department",
  "year_start": 2018,
  "year_end": 2021,
  "harm_type": "collective",
  "subject_count_estimate": null,
  "subject_identification": "anonymous_collective",
  "oversight_trigger": "internal_audit",
  "oversight_date": "2021-08-24",
  "remedy_status": "partial",
  "documentation_status": "verified",
  "summary_50w": "Chicago's Office of Inspector General analysed more than 50,000 ShotSpotter alert and dispatch records from the Chicago Police Department. It found that 9% of alerts with a reported disposition indicated a gun-related offence, and that officers cited aggregate ShotSpotter alert frequency in an area as partial grounds for investigatory stops and pat-down frisks of civilians.",
  "sources": [
    {
      "type": "other",
      "title": "Chicago Inspector General: Using ShotSpotter Does Not Justify Crime Fighting Utility",
      "url": "https://www.eff.org/deeplinks/2021/08/chicago-inspector-general-police-use-shotspotter-justify-illegal-stop-and-frisks",
      "publisher": "Electronic Frontier Foundation",
      "date": null,
      "access_date": "2026-04-23",
      "is_primary": false,
      "notes": "Originating report"
    },
    {
      "type": "other",
      "title": "OIG Finds That ShotSpotter Alerts Rarely Lead to Evidence of a Gun-Related Crime and That Presence of the Technology Changes Police Behavior",
      "url": "https://igchicago.org/2021/08/24/oig-finds-that-shotspotter-alerts-rarely-lead-to-evidence-of-a-gun-related-crime-and-that-presence-of-the-technology-changes-police-behavior/",
      "publisher": "City of Chicago Office of Inspector General",
      "date": null,
      "access_date": "2026-10-10",
      "is_primary": true
    },
    {
      "type": "other",
      "title": "The Chicago Police Department's Use of ShotSpotter Technology",
      "url": "https://igchicago.org/wp-content/uploads/2023/08/Chicago-Police-Departments-Use-of-ShotSpotter-Technology.pdf",
      "publisher": "City of Chicago Office of Inspector General",
      "date": null,
      "access_date": "2026-10-10",
      "is_primary": true
    }
  ],
  "tags": [
    "gunshot_detection",
    "stop_and_frisk",
    "racial_disparity",
    "inspector_general_report",
    "acoustic_surveillance"
  ],
  "extraction_metadata": {
    "first_collected": "2026-04-23T06:48:38.255730+00:00",
    "last_verified": "2026-10-10T16:06:44.084191+00:00",
    "verified_by": "human_review"
  }
}