Professor Hammitt's research concerns the development and application of quantitative methods—including benefit-cost, decision, and risk analysis—to health and environmental policy. Topics include management of long-term environmental issues with important scientific uncertainties, such as global climate change and stratospheric-ozone depletion, evaluation of ancillary benefits and countervailing risks associated with risk-control measures, and characterization of social preferences over health and environmental risks using revealed-preference, stated-preference, and health-utility methods. He has served on six National Academies of Sciences panels and more than a dozen advisory committees to the U.S. Environmental Protection Agency and other government agencies. He received the Distinguished Achievement Award from the Society for Risk Analysis in 2015 and the Outstanding Achievement Award from the Society for Benefit-Cost Analysis in 2021 and is a fellow of both societies.