Homicides: Why do Chicago Police and the medical examiner’s office report different totals?

Homicide Watch Chicago Editor

When looking at annual homicides in Chicago there are two numbers that should be considered — those provided by the Chicago Police Department and those provided by the Cook County Medical Examiner’s office.

Chicago Police and the medical examiner’s office are the two primary reporting agencies, however, the two use different methods for compiling their numbers.

The medical examiner’s office rules a death a homicide if one person caused the death of another — although auto crashes can be ruled homicides or accidents. The medical examiner’s office number includes people shot and killed by police officers, crashes ruled homicides and killings in city limits investigated by Illinois State Police.

The medical examiner’s office total also includes homicides ruled justified by Chicago Police. For example, if a store owner shoots and kills a person trying to rob the store at gunpoint that is a homicide on the medical examiner’s office tally, but not on the Chicago Police list because it was ruled justified.

The Chicago Police number is any slaying where detectives determine one person intentionally killed another and murder charges will sought through the state’s attorney’s office. Because the Chicago Police number is based on intent, it can sometimes take days or weeks for police to classify a killing as a murder.

Currently, the medical examiner’s office has reported 443 homicides (including police-involved shootings) and Chicago Police have reported 410 through Dec. 26.

Over the past six years, the medical examiner’s office has always reported more homicides than Chicago Police, but the percentage in change from year to year is about the same.

Red Eye Chicago has been tracking the Cook County medical examiner’s office numbers since 2007. The Red Eye number does not include people shot and killed by police.

Here is a comparison between the Chicago Police number and the medical examiner’s office number minus police-involved shootings.

Chicago Police numbers:

2008: 513
2009: 459 (- 11 %)
2010: 436 (-5 %)
2011: 435 (No change)
2012: 503 (+14 %)
2013: 410* (-18 %)
* Number through Dec. 26

Medical examiner’s office numbers:

2008: 528
2009: 463 (-12 %)
2010: 455 (-2 %)
2011: 451 (-1 %)
2012: 521 (+13 %)
2013: 432 (-17 %)

The medical examiner’s office has reported more homicides than police each of the past six years. During that time, the average difference is 16 more per year.

However, the percentage changes from one year to the next are about the same, so when looking at whether murders were up or down between years it doesn’t matter whose numbers are used.

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