A recent study by a pair of Harvard University researchers tries to map the activities of Mexico's drug trafficking organizations using a query algorithm in Google.

One of the key results is that these major groups operate in just 713 of the country's 2,441 municipios — a jurisdiction roughly equivalent to a county in the United States. That's 29 percent of the municipios in Mexico.

"Large areas of the country completely lack the presence of a drug trafficking organizations," authors Michele Coscia and Viridiana Rios conclude. "Our data changes our understanding of criminal territoriality, showing that drug trafficking organizations pick their areas of operation quite selectively."

They present their Google-searching method as a way to gain broad information on illicit activities, despite the relative secrecy of the actors. They used searches of news organizations, online forums and specialized blogs, among other sources.

They tested their results by using the same method to search for the activities of governors of Mexican states and finding that the results showed the governors' activities were concentrated largely in their home states.

"We use the web because it is an extremely valuable depository of up-to-

date, public, and private information. Data that used to be secret and dffiicult to access is now publicly shared, discussed and posted on specialized blogs and forums," Coscia and Rios write.

I don't have the expertise to evaluate whether this is a legitimate way of tracking criminal groups. However, a quick review of the maps available in this 15.9 mb PowerPoint presentation raises questions for me. Why, for example, does the Juarez Cartel appear active in a border municipio in the highlands of far northeastern Sonora in 2001, but not in Ciudad Juarez or the whole of Chihuahua state?

Still, what a fascinating approach to an intractable topic.