Chicago’s Homicide Resolution Rate

The editors of the Chicago Sun-Times seem surprised to learn that the statistics used to measure the performance of law enforcement agencies are specifically designed to make them look good:

To counter 2021’s grim homicide statistics, Chicago Police Supt. David Brown has touted the increased number of murders considered “cleared”: 400 in 2021, the most in 19 years, Brown says. Based on the official CPD tally of 797 homicides last year, that’s a clearance rate of just over 50%.

But 199 of those cases were closed “exceptionally,” which means no one was charged. And one in seven cleared cases involved a murder committed more than 10 years ago.

In all, CPD actually made arrests in fewer murder cases than in 2020, when 209 people were charged.

CPD, it must be noted, still has too few detectives to investigate homicide cases. Recent hires have helped, but additional hiring must be a top priority.

As well, CPD uses the FBI’s formula for calculating homicide clearances, dividing the number of all cases solved, no matter when a murder took place, by the number of homicides in a given year.

Using the FBI’s formula sounds reasonable. It’s better to solve a murder years later than not at all, and detectives deserve credit when they do so. But solving more murders, more quickly, is essential, particularly when Chicago has more homicides than New York or Los Angeles, which are much larger.

A spokesperson for Foxx cites state laws that raised the bar for evidence in murder cases as the reason why prosecutors last year turned down the most cases ever in Foxx’s six-year tenure. Which begs the question: Is the same happening in other state’s attorney’s offices across Illinois?

The public deserves answers to that question and others, given widespread skepticism about Foxx’s track record on crime-fighting.

Let’s make a stab at translating that 50% clearance rate into an estimate of in how many of last year’s homicides someone was charged. My back-of-the-envelope calculation for the actual clearance rate of last year’s homicides is 18%. That sounds considerably worse than “just over 50%”, doesn’t it?

Don’t worry. I’m sure that Mayor Lightfoot’s recently announced firearm “turn-in” program will result in a dramatic reduction in gun violence in the city. Despite such programs having produced such poor results in the past.