  Cannabis is the most common illicit drug, and understanding its demand is
relevant to analyze the potential implications of its legalization. This paper
proposes an endogenous three-part model taking into account incidental
truncation and access restrictions to study demand for marijuana in Colombia,
and analyze the potential effects of its legalization. Our application suggests
that modeling simultaneously access, intensive and extensive margin is
relevant, and that selection into access is important for the intensive margin.
We find that younger men that have consumed alcohol and cigarettes, living in a
neighborhood with drug suppliers, and friends that consume marijuana face
higher probability of having access and using this drug. In addition, we find
that marijuana is an inelastic good (-0.45 elasticity). Our results are robust
to different specifications and definitions. If marijuana were legalized,
younger individuals with a medium or low risk perception about marijuana use
would increase the probability of use in 3.8 percentage points, from 13.6% to
17.4%. Overall, legalization would increase the probability of consumption in
0.7 p.p. (2.3% to 3.0%). Different price settings suggest that annual tax
revenues fluctuate between USD 11.0 million and USD 54.2 million, a potential
benchmark is USD 32 million.
