How Does Legalizing Cannabis Reduce the Amount of Kids Going into Foster Care by 10%?

We estimate the effects of legalized recreational marijuana on entry into the foster-care system. Exploiting state-level variation in legalization and its timing, we estimate that legalization decreases foster-care placements by at least 10%, with larger effects in years after legalization, and for admissions for reasons of parental drug and alcohol abuse, physical abuse, neglect, and parental incarceration. Our findings imply that legalization may have important consequences for child welfare, and that substitution toward marijuana from other substances can be an important part of how legalization affects admissions.