September 14, 2011

City of Chicago Releases Ten Years of Detailed Crime Data

Unprecedented release of data invaluable resource for community policing organizations, criminal justice research, residents of Chicago

Mayor's Press Office    312.744.3334

Mayor Rahm Emanuel today announced that over 4.6 million crime incident reports spanning back over 10 years is now available online and updated daily on the City of Chicago’s data portal. This data set release is part of Mayor Emanuel’s ongoing efforts to increase transparency and provides an invaluable resource for criminal justice research institutions, community policing organizations, journalists and residents invested in making their neighborhoods safer.

“By posting this data online, we are providing a resource that will significantly impact criminal research while allowing community organizations to more effectively collaborate with the Chicago Police Department and better understand where crime is happening in their neighborhoods, streets and corners,” said Mayor Emanuel.

Prior to the release of this data set, crime data was only publicly released in aggregate forms on a monthly basis, and incident crime data going as far back as 90 days was available on the Police Department’s CLEARMAP geographic data system. Starting today, specific incident data going back 10 years is available online on the City’s Data Portal and updated almost daily.

To date the Mayor’s Office has released over 200 datasets, including salary information, city contracts, lobbyist disclosures, debarred vendors and abandoned buildings. All of the data sets, including today’s crime data, can be found at Since May 16, 2011, the City of Chicago’s open Data Portal has logged more than 430,373 views.

“This type of data is in very high demand from community organizations, and this will forever change lives of the people working in neighborhoods to combat crime because they can target interventions in ways they couldn’t before, down to the block and down to the individual crime,” said Virginia Carlson, President of the Metro Chicago Information Center (MCIC), an independent research group that provides demographic and baseline data on social policy and is a member of the National Neighborhood Indicators Partnership. “Open information like this is absolutely unprecedented in Chicago and the nation.”

Chicago joins a number of other cities, including New York, Los Angeles, Phoenix, Houston and Philadelphia, which have begun posting crime data online. However, the release of a crime data set of this size, scope and format is unprecedented nationally. 

"Government transparency is so important to the public and fundamental to establishing legitimacy," said Dennis Rosenbaum, a Professor of Criminology, Law and Justice at the University of Illinois-Chicago. "The academic community will use these data to generate new knowledge about patterns of crime, educate the public, and improve strategies for reducing crime in Chicago and across the country. The research opportunities are significant, and the more minds you have working on the data, the better our understanding of crime and the greater our ability to translate these findings into improved community safety."

The release of this data is a part of the Chicago Police Department’s commitment to providing resources to and supporting community policing organizations. Also, having the information available online will help provide greater accountability and transparency in the Chicago Police Department while providing another tool for a historical evaluation of performance and trends by crime type and geographic location. The format also saves time and money by eliminating the resources necessary to pull together FOIA requests and non-disclosure agreements for university research projects that in the past have taken as much as a year to fulfill. For privacy protection or to preserve the integrity of an ongoing investigation, certain confidential cases are not included in the data set.