We study how the societal disruptions of the COVID-19 pandemic impacted diagnosis of a prevalent childhood mental health condition, Attention Deficit Hyperactivity Disorder (ADHD). Using both nationwide private health insurance claims and a single state's comprehensive electronic health records,...

Thirty-four states have adopted medical marijuana laws and ten states have adopted recreational marijuana laws. There is little research comparing how these two types of laws affect drug consumption. Using a difference in difference strategy, we find that recreational laws increase past-year...

Vaccines influence the course of pandemics both directly, by protecting the vaccinated, and indirectly, by reducing transmission to the unvaccinated, a key externality. Estimating direct effects is challenging because of selective vaccine take-up; estimating indirect effects also poses...