For four years, RedEye has been mapping locations of Chicago homicides both online and in the newspaper. Over the years, readers have wanted to know more about homicides and RedEye's data collection methods. Here are the answers to the most frequently asked questions.
How does RedEye count homicides?
RedEye collects information about homicides from the Cook County Medical Examiner's Office, which performs autopsies on bodies to determine the causes of death. If the Medical Examiner's Office rules that a person died of a homicide in Chicago, RedEye will log the death in its database.
For the most part, RedEye and the Chicago Police Department have similar data, but there are two main differences in the counts. First, RedEye logs deaths by the date the incident occurred, not the date of death.
For example, last year, the Chicago Police Department included seven victims in its 2012 homicide count who were shot earlier than 2012 but died last year. One of the victims was shot in 1986 but died in February. RedEye will list those cases in the database for the year in which the incident occurred, dating back to 2007, to provide an accurate picture of violence that occurred during those times.
Second, because the map is of homicides and not murders, RedEye also includes cases where the Medical Examiner's Office has ruled the death a homicide but murder charges were not brought against the offender. These cases are typically shootings that the police have deemed to be accidental or in self-defense.
Neither the police nor RedEye include police-involved shooting deaths in their counts when they occur in the line of duty.
Where does the information about the victim's race come from?
For the most part, information about a victim's race comes from the Cook County Medical Examiner's Office, which assigns one-letter race designations ("B" for "Black") on its daily record log. For victims of Hispanic ethnicity, the Medical Examiner's Office typically pairs an "H" with "W" for "White." RedEye also takes its cues from the U.S. Census Bureau, which considers "Hispanic" to be an ethnicity and not its own separate race.
What is the most common type of homicide?
In 2012, the majority of homicide victims are young black men killed by gunfire on the South Side. Gunshot homicides comprised about 86 percent of the 515 homicides last year. Nearly 77 percent of the victims last year were black. About 63 percent of the victims were between the ages of 13 and 29, RedEye data shows.
How often are homicide cases solved?
The percentage of cases the police department says it has solved is a constantly changing number. This year, charges have been filed in about 20 percent of cases, according to RedEye data of Wednesday afternoon. From year to year, it appears that Chicago Police typically have a 24 percent clearance rate.
Where can I find more information about homicides?
RedEye homicide data is available at redeyechicago.com/homicides. For Chicagoans seeking more information, the police department maintains a database of all crimes at data.cityofchicago.org. The department has a posting lag time of about 10 days after an incident occurred.
Track every Chicago homicide by neighborhood, age, race and more on our homicide map and follow along with our coverage of Chicago violence here.
Want more? Discuss this article and others on RedEye's Facebook page.