1. School of Management, Xi'an Jiaotong University, Xi'an, Shaanxi Province, 710049, China, and Morrison Institute for Population and Resource Studies, Stanford University, Stanford, CA 94305, USA
2. Institute for Population and Develoment Studies, School of Public Policy and Administration, Xi'an Jiaotong University, Xi'an, Shaanxi Province, 710049, China
3. Morrison Institute for Population and Resource Studies, Stanford University, Stanford, CA 94305, USA
4. Center for Public Administration and Complexity Science, Xi'an, Shaanxi Province, 710049, China