This report shows that the Chicago Police Department has a current practice of unlawfully using stop and frisk. Stop and frisk is disproportionately concentrated in the black community. Comparing stops to population, Chicagoans were stopped more than four times as often as New Yorkers at the height of New York City's stop and frisk practice. In the face of a systemic abuse of this law enforcement practice, Chicago refuses to keep adequate data about its officers' stops. The lack of data collection is a major impediment to understanding how stop and frisk policy is actually carried out on the streets. The report contains several improvements need to be made to provide greater transparency and make it possible for supervisors to fully review stops and frisks.