Water Productivity Assessment for the Yellow River Basin Ximing Cai 1 (Corresponding author), Yi-Chen E. Yang 1 , Claudia Ringler 2 , Liangzhi You 2 1 Department of Civil and Environmental Engineering, University of Illinois at Urbana- Champaign, email contact: xmcai@illinois.edu 2 International Food Policy Research Institute, Washington D.C.