Starting Wednesday, millions of crime statistics dating to 2001 will be posted online in a searchable database. It will be updated daily, providing fodder for residents to evaluate their own neighborhoods, academics to study crime and techie types to create websites or apps.
The crime-data sharing is the latest attempt by the administration of Mayor Rahm Emanuel, who took office in May, to make city dealings more open and counter Chicago's reputation for entrenched systemic corruption and backroom deals. Chicago officials recently posted online the salaries of city employees, city contracts and lobbying data, with more information expected in coming months.
"It's a whole new era of openness and transparency," said Brett Goldstein, the city's chief data officer and former police officer. "You determine your own analysis."
While some city critics are skeptical, Chicago's crime data release goes beyond what other major police departments do, crime experts say. Besides listing every crime over the past decade -- some 4.6 million incidents -- the database also lists each address, if there was an arrest, the police beat, city ward and case number. That includes everything from sidewalk arrests for marijuana possession to homicides.
An average person can already get details on a crime that happened the day before, but now they'll be able to look back over the past decade on their neighborhood, ward or entire city. It also increases the potential for more long-term studies by experts and, some hope, take steps toward crime prevention.
"It's big," said David Kennedy, director of the Center for Crime Prevention and Control at John Jay College of Criminal Justice in New York. "If not unprecedented, it's very unusual."
While no one tracks the some 15,000 police departments nationwide, a check of other major police departments that post crime statistics online shows nothing as comprehensive as Chicago.
Many, including Los Angeles, use a third-party company that maps data over a limited time period, generally a month or two. Los Angeles also has some historical data available, but it's through static reports or compilations of incidents. That information isn't searchable and a recent check showed links to several years were broken. Houston has a 30-day log. New York publishes weekly data, and has some historical data online, though the department has faced criticism for allegations of manipulating data and the police commissioner recently formed a unit to look into the claims.
The Seattle Police Department appears to come closest to what Chicago is attempting. It offers logs of 911 calls and has a searchable database, but the time and incidents aren't complete.
Prior to Wednesday, Chicago offered a 90-day glimpse of crime in a mapping tool. The city added a yearlong database earlier in the summer.
Chicago's data won't include some cases that are under federal investigation. Also, the database won't specify if the shooting was police officer-involved, for instance, though all homicides will be in the database, city officials said.
Some advocacy groups worry the information doesn't go far enough because it doesn't include race or detailed police reports.
"It would be one small step in the right direction," said Tracy Siska, executive director of the Chicago Justice Project, which helps increase public access to information. He called the police department's reputation "horrible" when it comes to doling out information, citing an incident last year when the group waited 78 days to release details on the sexual assaults, he said.
Also he said such massive information dumps aren't always user friendly to the average person. City officials recognized that fact, but Goldstein said there are more benefits to making raw data available to everyone.
He said those who stand to benefit the most are academics and journalists because the data will be in one place, cutting down on Freedom of Information Act requests and other time-consuming and costly requests for records.
Yale University professor Tracey Meares, who has long studied Chicago crime, said it sends a message to academics that the Chicago Police Department is "an agency that's willing to share."
"That kind of transparency is a good idea," she said.