Chicago police misconduct happens in groups, study finds A new analysis of public data about CPD members finds that their misconduct, often portrayed as a matter of "bad apples," is a group phenomenon and inflicts outsized harm in minority communities.
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Chicago police misconduct happens in groups, study finds

Chicago police misconduct happens in groups, study finds

A new analysis of public data about Chicago Police Department members finds that their misconduct, often portrayed as a matter of "bad apples," is a group phenomenon and inflicts outsized harm in minority communities.

The researchers used social-networking algorithms and machine-learning techniques to analyze data from seven sources spanning nearly five decades. The analysis came up with 160 "potential crews" of deviant, even criminal, cops. Those groups include 1,156 past and present officers.

"These are the worst of the worst cops coming together," Northwestern University sociologist Andrew Papachristos, who led the research, told WBEZ, saying the police crews operated in some ways like street gangs. "They had codes, they had symbols, they were aggressively targeting competition. They were engaging in criminal behavior."

Papachristos said CPD could use the analysis's methodology to develop an early warning tool enabling the department to break apart cop crews before they severely set back the department's crime-fighting efforts.

The crews flagged by the study represent less than 4% of police officers in the data, according to the analysis, but account for about a quarter of documented CPD use-of-force complaints, city payouts from litigation and shootings by cops. The detected crews also contributed to racial disparities in arrests and generated nearly 18% of complaints filed by Black Chicagoans and 14% filed by Latinos.

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The study was published Wednesday by PLOS One, a peer-reviewed journal of the San Francisco-based Public Library of Science. The datasets, mostly obtained by the nonprofit Invisible Institute through open-records requests, include misconduct complaints, personnel records, unit assignments, lawsuit settlements, arrests, use-of-force reports and officers in known crews. The study focused on 1971 to 2018, though some of the datasets covered only part of that period.

Early warnings

To calibrate their detection of CPD's potential crews, the researchers looked at characteristics of three well-documented deviant police outfits that operated for years within the department.

Those crews include a tactical unit led by former Sgt. Ronald Watts that was under investigation for more than a decade for allegedly pinning false cases on residents of a South Side public housing complex and stealing money from drug dealers.

Watts and one of his underlings were arrested in 2012 and sent to federal prison for stealing what they thought was drug money from an FBI informant. The scandal has led judges to throw out 213 convictions tied to Watts, including 44 last month in Cook County's largest mass exoneration ever.

The data attributes of those three well-documented criminal-cop crews set the parameters for detecting other potential CPD crews.

The researchers say they took steps to avoid flagging officers as part of potentially criminal crews merely because those cops ended up assigned to the same units as the deviant officers. They say they also tried to distinguish misconduct from hard work.

Papachristos said the deviant 4% of officers had arrest rates three times higher than the rest of the department but said plenty of other officers had high arrest rates: "Those other aggressive police officers aren't forming crews."

CPD over the years has set up multiple "early intervention" systems to flag problem officers. The department's consent decree, a court-enforceable police reform agreement, requires a system enabling supervisors to "proactively identify at-risk behavior by officers under their command."

That system, according to the decree, must include data on uses of force, arrests, injuries and deaths in police custody, vehicle pursuits, misconduct complaints, criminal proceedings against officers and a host of other factors.

But, to the extent that officials have taken on criminal cops, efforts have largely focused on the officers as individuals "rather than the group behavior that supported it, tacitly condoned it, or at the very least didn't report it," Papachristos said. "We're trying to draw attention to [the reality] that it's much more than just an individual behavior."

Papachristos said he has shared his research on deviant cop groups with the department and that officials would be free to use his methodology for an early warning system focused on those crews.

Many officers in the 160 crews detected by the study remain active CPD members, Papachristos said.

The department could respond in a range of ways to break up the crews even if it lacked solid evidence for criminal or disciplinary charges, Papachristos said.

"As soon as you start seeing bad behavior, you can ... put them on different shifts, put them in different districts, on different assignments," Papachristos said.

The article says intervening in the police crews would improve the relationship between the community and the police and, ultimately, improve public safety.

"The duty to protect and serve is one of the things that the police are supposed to do," Papachristos said. "But that also means protecting from bad police officers."

CPD spokesmen, provided with the article, did not immediately respond with comment or answer questions about identifying and breaking apart police crews exhibiting signs of possible misconduct.

In the past, Papachristos's work on social networks has helped cities identify community members at greatest risk of shooting a weapon or being shot and to target them with social interventions.

In a 2013 Washington Post op-ed, Papachristos wrote that gun violence spreads through social networks much like "public health epidemics such as cholera in Haiti or HIV/AIDS in the United States."

Chip Mitchell reports out of WBEZ's West Side studio about policing. Follow him at @ChipMitchell1. Contact him at

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