John reports on an article by Oeindrila Dube and Suresh Naidu, who ran some regressions on observational data and wrote:
This paper examines the effect of U.S. military aid on political violence and democracy in Colombia. We take advantage of the fact that U.S. military aid is channeled to Colombian army brigades operating out of military bases, and compare how changes in aid affect outcomes in municipalities with and without bases. Using detailed data on violence perpetuated by illegal armed groups, we
find that U.S. military aid leads to differential increases in attacks by paramilitaries . . .
It’s an interesting analysis, but I wish they’d restrained themselves and replaced all their causal language with “is associated with” and the like.
From a statistical point of view, what Dubey and Naiduz are doing is estimating the effects of military aid in two ways: first, by comparing outcomes in years in which the U.S. spends more or less in military aid; second, by comparing outcomes in cities in Colombia with and without military bases. Continue reading →