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.

The 2009 homicide numbers collected by the SNSP (National System of Public Security) are finally out, you can download the data from the ICESI, which is a civic institution not affiliated with the government.

If you remember, one of the conclusions from my statistical analysis of the drug war was that:

The police records in 2008 are missing more than a thousand homicides in Chihuahua! Just to give you some perspective, in Ciudad Juarez, Chihuahua’s biggest city, there were more than 1,600 homicides, more than the 1,414 reported in the whole state according to police records. I strongly recommend against using data obtained from the police records from the SNSP or the UN homicide statistics if you need the latest homicide numbers.

In the latest incarnation of the data, the number of homicides in Chihuahua in 2008 were updated to 2,030 and now resemble the numbers from the Statistical Yearbooks; however, you can still download the data as it appeared in 2008 from the ICESI. At least the SNSP realized that the 2008 numbers were ridiculously low. But what about 2009, well…

I can’t compare the police records to the vital statistics since they won’t be out until November or December, but I can compare them to press reports.

In Ciudad Juarez there were 2,642 homicides during 2009, but according to the police data, in the whole state of Chihuahua there were 2,523 homicides, sigh… history repeats itself.
For the whole of Mexico there were 15,255 homicides, which if the number is to believed would correspond to a homicide rate of 14.2. I obviously don’t trust the data and stand by my assertion that the homicide rate according to the vital statistics from the INEGI will be closer to my prediction of 15.5 than 14.2.

This is getting to be completely ridiculous. The code to generate the chart is after the jump.

On December 11, 2006 Felipe Calderon, as the first significant act of his presidency, sent the army to his home state of Michoacan. He claimed that it was to regain control of territories lost to the drug cartels, and indeed, a new cartel had started operating in Michocan. But the fact that he won the election by the slim margin of 0.6% and his main rival declared himself the legitimate president of Mexico surely influenced him.

In the beginning, the war proved a success by all objective measures: in 2007 the homicide rate decreased to its lowest level in recorded history and murders in Michoacan went down by more than 40%. Not that it mattered much, all the while the government was losing the psychological war—the use of torture and beheadings became common in executions carried out by drug cartels as they sought to protect their turfs and intimidate the population.

And then 2008 rolled around and the Sinaloa Cartel decided to take advantage of the weakening of the other cartels and the corruption that is endemic in Mexico to gain control of the drug trade…

Sources: Homicide data from INEGI, population data from CONAPO. 2009 estimate based on execution rates