He is also a guest researcher with the Population and Climate Change Program at the International Institute for Applied Systems Analysis in Austria. He holds a PhD in environmental sciences (demography) from the University of Amsterdam, and an MA and BA in sociology from Peking University. He conducted post-doctoral research at the Max Planck Institute for Demographic Research and was also a visiting scholar at Indiana University, the Vienna Institute of Demography of the Austrian Academy of Sciences, and the University of Amsterdam. Before coming to Brown, he was an associate professor at Peking University. His work has been funded by the Wellcome Trust Foundation, the World Bank, the China Natural Science Foundation, and a National Key Research Project in China.