There have been some very good visualizations of the Wikileaks data so I decided to create one of the drug war in Mexico

Ciudad Juárez became the most violent city in Mexico as a consequence of the vicious war between the Juárez Cartel and the Sinaloa Cartel. So far more than 6,500 people have been murdered in this city since the war started. With the Juárez Cartel significantly weakened, 2010 is set to be the most violent year yet…

Here are some statistics of the dead of Juárez:

OpenHeatMap is an open-source tool that lets you turn a spreadsheets into a maps. It is very user-friendly if you have lots of data because it allows you to zoom into the map, and if you’re like me and can never remember the exact location of important cities, when you hover your mouse over a region it shows you its name and the exact value you assigned it.

But best of all Pete Warden just updated OpenHeatMap with maps of Mexico at the municipality level. I decided to take advantage of this and built a HeatMap/Choropleth of the murder rate in Mexico for the last three years (the drug war started December 2006).

The spreadsheet I used to build the maps looks like this:

mex_muni_code	value	time
01001	3.1	2006
01001	3.9	2007
01001	5.7	2008
01002	2.4	2006
01002	2.4	2007

The mex_muni_code column corresponds to the combined state and municipality codes, the value column is the homicide rate, and time is an optional column if you want the map to have a slider so you can compare homicide rates over time. Once the spreadsheet is ready all you have to do it is upload it and you’re set to go.

There has been a lot of attention paid to the role of US guns exacerbating the violence in Mexico. The assault-weapon ban expired on September 14, 2004, but with the recent spiraling of violence in Mexico the ban has attracted renewed attention. Just recently the Mexican President stood before the American Congress and blamed the assault weapon ban for the rising violence in Mexico, seemingly without proof. This post will try to clarify some of the issues surrounding the controversy.

I think it would be fair to say that the conventional wisdom by scholars who have studied the ban would be the one Christopher Koper, Daniel Woods and Jeffrey Roth stated: “We cannot clearly credit the ban with any of the nation’s recent drop in gun violence.” In other words, the assault weapon ban had no significant effect—at least where the United States is concerned. And as far as I know there are no studies of the effect of the ban expiration on Mexico.

As is well known, gun control is politically charged issue, not only in the United States, but also in Mexico. For example, after two students died in a shootout between the army and cartel gunmen, the rector of what is arguably Mexico’s best university stated:

For me [Rangel Sostmann] the solution is that Mexico and the United States must change their policies. And the policy right now is for the United States to send the money and weapons, and Mexico puts the dead and the drugs. And that ultimately is not going to work, it’s not a question of driving the Army out, the problem is that you have to change the policies, in this case the United States policy.
—Rangel Sostmann, ITESM Campus Rector

Later an investigation by the National Human Rights Commission concluded that the army had used excessive force, impeded the investigation, planted weapons on the students, possibly tortured them for several minutes, and then shot them at point blank range. The day after the report was released, the ITESM bestowed upon the Secretary of Defense the “AdHonorem” award, given to persons whose works have contributed in an outstanding manner to the “the fight against injustice.” As you can see gun control has become extremely politicized, to say the least.

With politics hopefully out of the way, let’s look at the homicide data with a seasonal decomposition by loess:
As you can see from the charts there was an increase in the number of homicides and homicides with firearm that coincided with the expiration. The big drop at the start of 2007 was due to the military operations in Michoacan and Acapulco, and also to a temporary drop in the homicide rate of Mexico City (which had nothing to do with the drug war).

Last year there were over 2,600 murders in Ciudad Juarez, and if the more than 1,800 murders so far this year are any indications, there will be even more murders in 2010. Ciudad Juarez is a scary place, but it wasn’t always that way…

I learned from Noel Maurer’s Blog that Ciudad Juarez used to have a low murder rate before 1993, but it rose steeply after the local leader of the Juarez Cartel, Aguilar Guajardo, died, and Amado Carillo replaced him. After Amado Carrillo had firmly established himself thing calmed down somewhat, but by then the violence had switched to a new equilibrium. But anyways, go read Noel Maurer’s take on it

The director of the CISEN, the Mexican agency in charge of generating intelligence to safeguard Mexico’s security, said in a presentation yesterday that the number of homicides linked to the drug war was a little over 28,000 since the start of the Calderon administration.

Guillermo Valdés didn’t provide the raw data so I used Engauge to digitize the slide with the homicide data from the presentation:

I’ve been complaining about how homicide statistics from police sources were too low in 2009, with the entire state of Chihuahua having less homicides than its biggest city. I was thinking of finding out if I could use the IFAI (Freedom of Information Access) to obtain the original CIEISP forms which the state police forces are supposed to fill out each month and send to the National System of Public Security (SNSP) for tallying, to see if there were any unusual patterns, but someone beat me to requesting the data.

You can see the request here, and download the excel file with the CIEISP forms here.

The main difference between the datasets is that the CIEISP forms usually report lower numbers than the data the SNSP gave to the ICESI. This is not surprising since the CIEISP forms have no recorded homicides in some states during the last months of the year (the request was made in December 2009), but the numbers for Chihuahua in both datasets are identical, with a total of 2523 homicides recorded. More importantly, in the months of November and December there were no homicides registered in the CIEISP forms, and the data for October looks incomplete. That’s the reason Chihuahua had such a low homicide rate according to the police, the data they gave to the ICESI only includes 9¾ months of homicides.

I’m surprised by how similar the trends are (excluding the drug war in Mexico). There were big decreases in the homicide rate in all three countries starting in the early nineties, which then slowed down around 2000.

The municipalities are ordered by their peak homicide rate and the dotted gray line is the average homicide rate over the 2005–2008 period. Since homicide is mostly a male phenomenon it’s not surprising to find Ciudad Juarez is the most violent city for men.