CHICAGO (CBS) — In the wake of multiple reports questioning the accuracy of the Chicago Police Department’s multimillion-dollar network of ShotSpotter gunshot detection sensors, a coalition of aldermen is seeking to hold public hearings on whether the city should continue its contract, but their effort ran into a roadblock on Tuesday.

Last month, the city’s inspector general published a report that found ShotSpotter alerts rarely lead officers to evidence of an actual gun crime. Those findings are consistent with a recent study by the MacArthur Justice Center at Northwestern University, which also found nine out of 10 times, noises detected by ShotSpotter sensors did not lead to any evidence of an actual crime.

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A group of 16 aldermen, most of them members of the City Council’s Progressive Caucus, on Tuesday introduced a resolution calling for the Budget and Public Safety Committees to hold a joint hearing this fall, before the 2022 budget plan is approved, “to assess the reliability of ShotSpotter and assess whether the City of Chicago should extend, amend, or discontinue its contractual relationship with ShotSpotter, Inc.”

That comes just weeks after the CBS 2 Investigators reported the city quietly extended its contract with ShotSpotter, for two more years, without public input. The contract originally had been set to expire last month, but was extended last December for an additional two years, with no public input or notice.

While some aldermen are now suggesting the city should reconsider its deal with ShotSpotter, their plan to hold a public hearing to assess the future of the contract was stalled when another alderman used a parliamentary maneuver to send the proposal to the Rules Committee, where measures opposed by the mayor are typically sent to die without a hearing.

They wanted to bring in top brass from CPD, as well as representatives from the Inspector General’s office and the MacArthur Justice Center to testify about the accuracy of ShotSpotter technology, but will now need to get the support of a majority of the City Council to send their proposal to the Budget and Public Safety to get that hearing.

A report from Inspector General Joseph Ferguson’s office last month found “ShotSpotter alerts rarely produce evidence of a gun-related crime, rarely give rise to investigatory stops, and even less frequently lead to the recovery of gun crime-related evidence during an investigatory stop.”

The CBS 2 Investigators have dug into CPD’s contract with ShotSpotter, and looked into accusations the technology doesn’t work as advertised, raising questions about whether the system is worth the $33 million price.

The Inspector General’s office analyzed data on ShotSpotter alert incidents between Jan. 1, 2020, and May 31, 2021. Their analysis found that of 50,176 alerts it reviewed, only 9.1% turned up evidence of a gun-related crime.

The acoustic gunshot detection system relies on hundreds of sensors placed on more than 117 square miles of city streets. Sounds detected by those sensors are analyzed by ShotSpotter acoustic experts and analysts at Chicago Police strategic decision support centers before officers are dispatched to respond to alerts of gunfire.

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“A large percentage of ShotSpotter alerts cannot be connected to any verifiable shooting incident,” the report states.

The report also notes that better data on the true outcomes from ShotSpotter alerts would help support City Hall’s assessments of whether to further extend its contract with ShotSpotter.

The use of ShotSpotter in Chicago has been controversial. The MacArthur Justice Center found the technology is mostly being used in Black and Latino communities. The American Civil Liberties Union also raised concerns. While activists called for the city’s $33 million contract to be cancelled, the CBS 2 Investigators learned, the city quietly extended it, for two more years, without public input.

Chicago police and ShotSpotter both repeatedly have said the technology is an important part of CPD’s goal of reducing gun violence.

In a statement last month after the inspector general’s report came out, a spokesperson for ShotSpotter insisted their technology is accurate:

“It is important to point out that the Chicago Police Department continually describes ShotSpotter as an important part of their operations. The OIG report does not negatively reflect on ShotSpotter’s accuracy which has been independently audited at 97 percent based on feedback from more than 120 customers. Nor does the OIG propose that ShotSpotter alerts are not indicative of actual gunfire whether or not physical evidence is recovered. We would defer to the Chicago Police Department to respond to the value the department gets from being able to precisely respond to criminal incidents of gunfire. We work very closely with our agency customers to ensure they get maximum value out of our service.”

The Chicago Police Department did not respond directly to CBS 2’s questions about the inspector general’s findings, including whether the department will use the findings to re-examine how it uses ShotSpotter technology as a crime prevention tool, whether it will change the way it tracks information on the efficacy of ShotSpotter, and if the department will revisit its extension of the ShotSpotter contract.

Instead, a CPD spokesman provided a nearly identical statement the department has provided in the past in regard to the ShotSpotter contract, defending the use of the technology as a “crucial” tool.

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“ShotSpotter has detected hundreds of shootings that would have otherwise gone unreported,” CPD spokesman Tom Ahern said last month, despite the findings that the vast majority of ShotSpotter alerts did not lead to evidence of a shooting.

CBS 2 Chicago Staff