More errors in the Mexican Mortality Database

on Sep 12, 2012

I've written before about how the deaths of the Acteal massacre weren't registered as homicides in the mortality database and about the large number of deaths of unknown intent in Ciudad Juárez. There's actually another large error in the database that occurred in January and February of 2007. Lots of accidents of unspecified injury mechanism were registered in the Federal District at the same time there was a never before seen drop in the number of homicides.

The drop didn't just involve homicides but also all kind of accidental deaths, though that is not an error but a drop in the quality of vital statistics data (I only show accidental deaths by cause of transportation in the chart for clarity purposes)
Loking at the data for the whole metro area of Mexico City broken down by state of occurrence one can see that the error only occurred in the Federal District (the spike during late 2007 in the State of Mexico is due transport accidents misclassified as unspecified, though it is difficult to see in the data due to seasonal patterns)
The ages of accidental deaths by unspecified cause that took place during January and February 2007 look different than those that occurred at other times.
The male to female ratio of accidental deaths by unspecified cause that took place during January and February 2007 look different than those that occurred at other times. During January and February more males than females died, just as in homicides and accidental deaths by cause of transportation.
I don't think there can be any doubt that some homicides "leaked" into accidental deaths by unspecified cause. I tried to classify the Jan-Feb accidents into homicides and accidents based on the characteristics of the dead (age, sex, place of occurrence) but given that the cause of death was left unspecified (firearm, suffocation, cut/pierce, etc) I was only able to obtain sensitivities and specificities of .60, which is only a little better than chance.

It looks as if the error didn't just happen in the Federal District but all over Mexico (though obviously no the state of Mexico). You see the same pattern of a big drop in homicides at the same time accidents by unspecified cause rise. Perhaps someone hired his dump brother in law to administer the database and he screwed things up?
The most worrying part is that the error coincided with the first military operations of the drug war. Perhaps the Mexican government saw the drop in homicides and became a little too cocky about its capacity to take on the drug cartels.

In Nuevo Laredo during the first months of 2007 there were more drug related homicides that total homicides according to the INEGI.

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Julie Devineau said...

Thanks Diego for highlighting those errors. I've found another one related to the homicides : the dreadful murder of 72 persons in San Fernando on august 2010. INEGI just counts 52 homicides that month in San Fernando. Here too, drug related homicides are higher than total homicides...

Diego Valle-Jones said...

Hi Julie, thanks for your comment, I mentioned the fact that the San Fernando Massacre was not recorded correctly in this post, also the 55 bodies found in the mass grave in the municipality of Taxco were not recorded in the database. I really ought to write a post listing all the errors in the INEGI database...

Julie Devineau said...

Right ! I had'nt read that post, thanks for the link. Looking forward to checking the 2011 data...

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Thank you for your interesting and insightful comments. I truly look forward to reading them.