Chicago crime stats: beware the “official” data in recent years

Chicago has a fascinating look at some interesting choices made about how to classify homicides in Chicago – with the goal of trying to reduce the murder count.

For the case of Tiara Groves is not an isolated one. Chicago conducted a 12-month examination of the Chicago Police Department’s crime statistics going back several years, poring through public and internal police records and interviewing crime victims, criminologists, and police sources of various ranks. We identified 10 people, including Groves, who were beaten, burned, suffocated, or shot to death in 2013 and whose cases were reclassified as death investigations, downgraded to more minor crimes, or even closed as noncriminal incidents—all for illogical or, at best, unclear reasons…

Many officers of different ranks and from different parts of the city recounted instances in which they were asked or pressured by their superiors to reclassify their incident reports or in which their reports were changed by some invisible hand. One detective refers to the “magic ink”: the power to make a case disappear. Says another: “The rank and file don’t agree with what’s going on. The powers that be are making the changes.”

Granted, a few dozen crimes constitute a tiny percentage of the more than 300,000 reported in Chicago last year. But sources describe a practice that has become widespread at the same time that top police brass have become fixated on demonstrating improvement in Chicago’s woeful crime statistics.

And has there ever been improvement. Aside from homicides, which soared in 2012, the drop in crime since Police Superintendent Garry McCarthy arrived in May 2011 is unprecedented—and, some of his detractors say, unbelievable. Crime hasn’t just fallen, it has freefallen: across the city and across all major categories.

Two quick thoughts:

1. “Official” statistics are often taken for granted and it is assumed that they measure what they say they measure. This is not necessarily the case. All statistics have to be operationalized, taken from a more conceptual form into something that can be measured. Murder seems fairly clear-cut but as the article notes, there is room for different people to classify things differently.

2. Fiddling with the statistics is not right but, at the same time, we should consider the circumstances within which this takes place. Why exactly does the murder count – the number itself – matter so much? Are we more concerned about the numbers or the people and communities involved? How happy should we be that the number of murders was once over 500 and now is closer to 400? Numerous parties mentioned in this article want to see progress: aldermen, the mayor, the police chief, the media, the general public. Is progress simply reducing the crime rate or rebuilding neighborhoods? In other words, we might consider whether the absence of major crimes is the best end goal here.

The most dangerous American neighborhoods

Walletpop.com has its second annual list of the most dangerous neighborhoods in America:

For the second year in a row, using exclusive data developed by Dr. Andrew Schiller’s team at NeighborhoodScout.com, and based on FBI data from all 17,000 local law enforcement agencies, WalletPop reveals the top 25 most dangerous neighborhoods with the highest predicted rates of violent crime in America.

This year, Chicago took the not-so coveted top spot from Cincinnati for the most dangerous neighborhood, while Atlanta has the highest number of neighborhoods making the list (four).

You may ask, why neighborhoods and not cities? Schiller explains that even the cities with the highest crime rates can have relatively safe neighborhoods, and thus it is less useful to generalize about an entire city.

The reason for looking at neighborhoods rather than cities is a good one – most American cities are quite large so city-level data is not very useful. To see the data for the Chicago neighborhood that tops the list, check out this page.

NBCChicago.com seems to have made an interpretation error with the data:

According to the info, anyone walking down Lake Street between Damen and Western has a 1 in 4 chance of being a victim of a crime.  Those who choose to live there face the same odds with the chances of being robbed.
As far as I can tell, the neighborhood crime rates apply to people living there for a full year, not people just walking in the neighborhood.
The website that this crime data was developed for, neighborhoodscoutreports.com, seems like it has some interesting proprietary data. When you enter a zip code, you can purchase a full report – though they leak out a few interesting tidbits. According to the website, zip code 60187 (Wheaton, IL) is “More sophisticated than 97%of U.S. neighborhoods. More walkable than 65%.”