Klein also holds a fellow position at the Center for Disease Dynamics, Economics and Policy, in Washington, D.C. He received his PhD in ecology and evolutionary biology from Princeton University and has held research associate positions at the Center for Disease Dynamics, Economics and Policy and Resources for the Future. Dr. Klein's interdisciplinary research involves ecology, epidemiology, economics, and human behaviour. His scientific interests include: factors that drive antimicrobial drug resistance; economic epidemiology; how human behaviour influences ecology/epidemiological dynamics; and how human behaviour influences evolution of an infectious disease.