Bo FengFollow

Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)


Public Management and Policy

First Advisor

Charles Courtemanche


Youth substance use remains a centerpiece of public policy. This dissertation characterizes the impacts of three policy decisions – legalizing marijuana, restricting access to electronic cigarettes, and raising cigarette excise taxes – on youth smoking, drinking, and marijuana use.

Chapter 1 uses Google search data to study the effects of marijuana legalization on youth marijuana use, by examining how information seeking on marijuana changed after states legalizing medical and recreational marijuana. Prior studies using survey data have found limited effects of medical marijuana legalization on youth marijuana use, and I show that this empirical regularity is also reflected in Google searches. In particular, legalizing medical marijuana influenced searches related only to news and not use or potential health concerns of use, but legalizing recreational marijuana boosted searches in all three dimensions. Linking state-level search data on marijuana use to the Youth Risk Behavior Surveys (YRBS), I find that stronger interest in use predicts higher levels of youth marijuana consumption, suggesting that recreational marijuana legalization may lead to increased marijuana use among adolescents.

Chapter 2 examines the effects of e-cigarette Minimum Legal Sale Age laws on youth cigarette smoking, alcohol consumption, and marijuana use. Using data from the national and state YRBS, we find that the laws increased youth smoking participation, approximately half of which could be attributed to smoking initiation. Limiting youth access to e-cigarettes has unintendedly made smoking more attractive, but we find little policy effects on youth drinking, binge drinking, and marijuana use.

Chapter 3 presents a new perspective on the disappearance of tax deterrent effects on teenage smoking in recent years. Motivated by the logic of price elasticity, we present evidence that the success of taxation can explain such disappearance because the ever-rising tax rates have nudged a significant portion of youth to quit smoking. Once the market is left only with those who are price insensitive, further tax hikes will naturally be less effective.