ZHANG Yaohui is professor of economics at the China Center for Economic Research, National School of Development, and Institute for Global health and Development, Peking University. She received BA and MA from Peking University and Ph.D. from the University of Chicago in 1995. Her research focuses on labor market issues in China, including determinants and consequences of rural to urban labor migration, wage differentials, and returns to education. Recently she has begun to conduct research in the economics of health and aging, such as the SES gradients of health, underdiagnosis of chronic diseases among the elderly, labor supply and living arrangements of the elderly, etc. Since 2007 she has been principal investigator of the China Health and Retirement Longitudinal Study (CHALRS), a nationally representative sample of Chinese residents 45 and older.