Chicago's gang data included contradictory, incomplete and implausible records—with no ordinary way for a person to know or challenge a designation.

Chicago OIG's review found systemic weaknesses in CPD's gang information practices: gang data existed in multiple repositories, lacked consistent controls, could contain contradictory information, and was shared with outside agencies. The review also found that people were not notified when they were designated and that CPD lacked a clear process for a person to challenge or correct a designation.

Contemporaneous reporting on records obtained from CPD found plainly implausible ages in the data, including purported gang members listed as 118 and 132 years old. The absurd records are useful not because anyone believed a 132-year-old was on the street, but because they demonstrate how basic data-quality failures can survive inside systems used for consequential decisions.

Sources: Chicago OIG review · ProPublica Illinois reporting