Stephen Ryan specializes in econometrics, environmental economics and health economics. His research spans industrial organization, applied microeconometrics, dynamic games and environmental regulation. He has published extensively in top-tier economic journals, including American Economic Review, Journal of Political Economy, Econometrica and Journal of Econometrics. His notable works cover demand estimation via machine learning, market-oriented emissions regulation, moral hazard in health insurance, teacher incentive schemes and the economic costs of environmental rules. Many of his papers are co-authored with leading scholars worldwide, showcasing his profound academic influence across multiple economic research fields.