Elaine M. Liu, a Professor of Economics at University of Houston, visited the NCID to give as seminar entitled "Externalities of Marijuana Legalization: Marijuana Use in Non-Legalizing States".

The paper reveals that social media connections can impact marijuana use in states where it remains illegal. Researchers used data on Facebook friendships to investigate whether connections to states where recreational marijuana is legalized affect marijuana consumption in non-legal states.

The findings indicate that areas with more connections to legalized states see a larger increase in marijuana use. This suggests that even distant, non-local connections can influence behavior. The study also highlights that traditional methods measuring the impact of marijuana legalization, like the difference-in-differences approach, may underestimate the direct effects on the state that has legalized marijuana.

These results underscore the importance of considering social networks when evaluating the consequences of policy changes.