Who would deny that friends, especially those in the same classroom, influence how much each other learn. This seems like a really important process to understand. It’s one of my research interests. Unfortunately it’s really hard!

Mark, over at Observational Epidemiology, links us to VOXEU for a paper attempting to shed light on the topic. The authors are economists, and they offer sophisticated econometrics in an attempt to estimate a truly causal effect. Unfortunately, the “treatment” effect, they attempt to identify is rather odd… the sum of one’s peers’ future educational attainment:

“We ﬁnd that a standard deviation increase in peers’ aggregate years of education (roughly two more high-school graduate friends) translates into roughly a 10 percent increase of a standard deviation in the individual’s education attainment (roughly 3.5 more months of education).”

One of the key generalizations the authors would like to make is that improving one student’s education, improves their friends’ educations. It seems that to inform that generalization, a better independent variable would be *the mean* of friend’s educational attainment, rather than the sum. There’s a lot more that could be said about the methodology, but I’ll hold off for now. Get the full paper, by Eleonora Pattachini and Yves Zenou, here.

Eleonora Pattachini and Yves Zenou (2011). Dynamic Aspects of Teenage Friendships and Educational Attainment Center for Economic Policy Research (February) Other: DP8223