Chicago Violent Crime in a Nutshell
I acquired Chicago violent crime data for a project on the effect of media violence on violent crime (I will post about this soon, I swear). As I was browsing the data, I noticed a very strange trend.
Most of the data looks like this:
10027862,04/10/2015 07:20:00 PM,BATTERY 10028400,04/10/2015 07:17:00 PM,BATTERY 10027915,04/10/2015 07:03:00 PM,ASSAULT 10028127,04/10/2015 07:00:00 PM,BATTERY 10027914,04/10/2015 07:00:00 PM,ROBBERY 10027859,04/10/2015 07:00:00 PM,BATTERY 10028087,04/10/2015 06:48:00 PM,BATTERY 10027831,04/10/2015 06:45:00 PM,BATTERY 10028119,04/10/2015 06:40:00 PM,BATTERY 10027829,04/10/2015 06:30:00 PM,ASSAULT 10031052,04/10/2015 06:30:00 PM,BATTERY 10028294,04/10/2015 06:24:00 PM,BATTERY 10028130,04/10/2015 06:00:00 PM,ROBBERY 10027783,04/10/2015 06:00:00 PM,BATTERY 10027785,04/10/2015 05:50:00 PM,BATTERY 10027846,04/10/2015 05:48:00 PM,BATTERY 10027786,04/10/2015 05:45:00 PM,BATTERY 10027767,04/10/2015 05:45:00 PM,BATTERY 10027736,04/10/2015 05:30:00 PM,ASSAULT 10027807,04/10/2015 05:25:00 PM,ASSAULT 10027903,04/10/2015 05:20:00 PM,BATTERY 10027874,04/10/2015 05:20:00 PM,BATTERY 10027898,04/10/2015 05:18:00 PM,BATTERY 10027756,04/10/2015 05:15:00 PM,BATTERY 10027781,04/10/2015 05:07:00 PM,BATTERY 10027960,04/10/2015 05:00:00 PM,BATTERY 10027737,04/10/2015 05:00:00 PM,ROBBERY 10027902,04/10/2015 05:00:00 PM,BATTERY 10027995,04/10/2015 05:00:00 PM,BATTERY 10027780,04/10/2015 04:57:00 PM,ASSAULT
But then when you get to New Years, a pattern starts to emerge.
9447124,01/01/2014 12:33:00 AM,ASSAULT 9902846,01/01/2014 12:30:00 AM,CRIM SEXUAL ASSAULT 9446760,01/01/2014 12:30:00 AM,BATTERY 9446848,01/01/2014 12:30:00 AM,BATTERY 9448651,01/01/2014 12:25:00 AM,BATTERY 9446789,01/01/2014 12:25:00 AM,BATTERY 9446832,01/01/2014 12:24:00 AM,ASSAULT 9446849,01/01/2014 12:20:00 AM,BATTERY 9446780,01/01/2014 12:20:00 AM,BATTERY 9446844,01/01/2014 12:15:00 AM,BATTERY 9446869,01/01/2014 12:14:00 AM,BATTERY 9446816,01/01/2014 12:10:00 AM,BATTERY 9446917,01/01/2014 12:10:00 AM,ROBBERY 9446764,01/01/2014 12:10:00 AM,BATTERY 9446958,01/01/2014 12:05:00 AM,ASSAULT 9574233,01/01/2014 12:01:00 AM,CRIM SEXUAL ASSAULT 9897526,01/01/2014 12:01:00 AM,CRIM SEXUAL ASSAULT 9447582,01/01/2014 12:01:00 AM,CRIM SEXUAL ASSAULT 9515113,01/01/2014 12:01:00 AM,CRIM SEXUAL ASSAULT 9925981,01/01/2014 12:01:00 AM,CRIM SEXUAL ASSAULT 9447168,01/01/2014 12:01:00 AM,BATTERY 9490406,01/01/2014 12:01:00 AM,CRIM SEXUAL ASSAULT 9613833,01/01/2014 12:01:00 AM,CRIM SEXUAL ASSAULT 9634981,01/01/2014 12:01:00 AM,CRIM SEXUAL ASSAULT 9659025,01/01/2014 12:00:00 AM,CRIM SEXUAL ASSAULT 9993250,01/01/2014 12:00:00 AM,CRIM SEXUAL ASSAULT 9593821,01/01/2014 12:00:00 AM,CRIM SEXUAL ASSAULT 9599640,01/01/2014 12:00:00 AM,CRIM SEXUAL ASSAULT 9728010,01/01/2014 12:00:00 AM,CRIM SEXUAL ASSAULT 9728020,01/01/2014 12:00:00 AM,CRIM SEXUAL ASSAULT 9448361,12/31/2013 11:55:00 PM,BATTERY
Let me know if you can spot the trend. Maybe, you might think to yourself, this is just a random occurrence. I promise, it is not. At first I thought that this must be some sort of sick crime-ring that the police busted one year. Unfortunately, that is not the case.
A Pattern Emerges
The following is a time-series plot of the last 15 years of criminal sexual assault in Chicago.
Those massive regularly occuring spikes? You guessed it, New Years.
Let’s zoom in a bit. Here is the same data over a four-year period.
And further in. One year, 2010.
Let us take it one final step. Here we are down to just two months: December and January. What will it look like?
This is so ridiculous. New Years accounts for a full 34% of all the sexual assaults that occur in the month of January.
##More Numbers The following is a description of the number of sexual assaults reported in Chicago in 2010.
count 381.000000 mean 3.742782 std 2.965056 min 1.000000 25% 2.000000 50% 3.000000 75% 5.000000 max 41.000000
According to these numbers, in 2010, you were 1,095% more likely to be a victim of sexual assault on New Years in Chicago versus the average day. I had to really think about how to format that percentage, since I don’t normally work with percents that high. That’s how high it is. That is almost 1,100% more likely! I’m not sure I can emphasize that.
Almost 1,100% more likely!!!
Alright, I emphasized it.
Chiacago’s performance record is getting better. However, I think it is important to note that 68% of sexual assaults go unreported.1 We are not just looking at 41 separate reported incidences of sexual assault on New Years (when one time alone is disturbing enough). What we are looking at is likely over 128 separate occurences of sexual assault. Seriously messed up.
In 2014, there were 1,234 separate reported incidences of sexual assault. That is 3,856 sexual assaults. In one year. In one city in America. Something is very wrong here.
We can speculate as to why. People are out with large groups of people they don’t know, they’re out late, and the alcohol is flowing. But still, the increase seems a little astronomical.
To some, maybe this seems like it would be obvious. However, I feel like parents and loved one’s are always giving out warnings for other holidays. “It’s Halloween, don’t take unwrapped candy.” “It’s St. Patrick’s Day, look out for drunk drivers.” But I have never once heard someone say, “it’s New Years, be careful, you might get raped.”
With part 2 of this post-series, I am planning a similar analysis extended to the rest of the violent crimes in Chicago. I’m hoping to finish a model predicting amount of crime per date for each category.
Thanks for reading, and be careful going out for New Years.
Justice Department, National Crime Victimization Survey: 2008-2012 ↩