Open Baltimore: Crime by month
Mayor Stephanie Rawlings-Blake's Open Baltimore initiative has made a trove of data about city crime available, and one of the first things I wanted to do with my limited technical skills was to use the crime by month data to analyze trends over the course of the year. We've long had access to weekly crime data, but haven't had a clean, month-by-month breakdown until now. One major hangup is that the data does not include December, but we'll work around that.
Since last year, people have been tweaking the city's crime declines as simply a function of the bad weather brought on by the "Snowpocalypse" early in the year. That's largely unfair, as there has been a sustained reduction in crime - particularly violent crime - going back three years now. But the data also confirms those assumptions that there was a dramatic plunge in most types of crimes in February, when the worst of the snow hit. Be it the overall cold weather, the snow, the fact that the month is the shortest of the year, or a combination of all three, February was unquestionably good for the bottom line.
Let's take a look first at property crimes:
As you can see, that's a drastic decline, particularly with larcenies and burglaries, which fell to nearly half of the totals recorded in the preceding month. They quickly snapped back in March, and continuing to climb as the whether got warmer, peaking in August. I'm struck less by the low totals in January and February than the relative consistency throughout the rest of the year. Keep in mind too that property crime might not necessarily have dropped to the extent we see here, but that police had limited ability to respond to such lower-priority calls for a stretch during the month.
What about violent crime? Homicides and shootings followed an expected pattern of rising and falling in the spring and fall. Robberies, however, followed a curious pattern.
Whether its an anomaly or some combination of street enforcement and other factors, robberies took a bizarre drop in June, even as the city recorded its highest number of aggravated assaults and third highest number of shootings. The June robbery figure was even 17 percent lower than the January total. I'll explore that in a subsequent post.
Lastly, here's a chart with reports of rape for 2010. You can see the huge spike after The Sun's story in June about the Police Department's ongoing "unfounding" of rape reports that prompted a change in policies for patrol officers and detectives:
Comments
THIS IS AWESOME.
Posted by: Evan | January 27, 2011 2:34 PM
I think the best way to see if we had a decrease in crime in 2010 would be to compare each category, month-by-month, to prior years. Can you give us a bigger graph of say 5 0r 10 years? I bet that would be interesting.
While that would be great, the data provided is for 2010 only. Year-end totals are easily accessible, but not month by month. -JF
Posted by: Pigtowner | January 27, 2011 3:40 PM
Well Justin. There in lies the problem. I applaud the city for finally releasing crime data to the masses. But if we have nothing to compare it to, then it is pretty useless data.
Madam Mayor...Chief Bealefeld...please give us the last 10 years of crime stats. Thank you.
If your goal is to compare overall crime to past years, the year-end data should suffice, no? The benefit of month by month would seem to be more about trend spotting and how seasons may affect crime...
By the way, here's a link to the yearly crime stats: http://www.goccp.maryland.gov/msac/crime-statistics.php
Posted by: Pigtowner | January 27, 2011 3:47 PM
The graphs show that the months with the most crimes are happening around July and August.. I think that the HOT weather helps to make the suspects feel like they can atemped and accomplish ANYTHING, GOOD OR BAD things. That is when they all should get together and go swimming @ the nearest pool. THANK YOU for reading my comment.
Posted by: Renee | January 27, 2011 7:15 PM
Here is a link to a downloadable file that has crime statistics for Baltimore City between 1975-2009 from some Maryland Government Office. This gives yearly statistics on all types of crime, although not monthly. I keep the spread sheet as an icon on my desktop for easy reference. It's amazing how many commenters make statistics up as they go along. A mild correction sets them straight.
Posted by: Cham | January 28, 2011 6:11 PM
A lot of what I already knew. Crime during the warm days (say when it's 60+ degrees outside at 2am) appear to happen more often. In fact, when the weather gets warmer I worry more about my car being broken into or my shed being broken into then I do on days like today when we are projected to have a high of less than 30 degrees and snow on the way.
Posted by: Phillip | January 31, 2011 2:10 PM