Stanford University - Department of Economics, University of Michigan at Ann Arbor, University of Pittsburgh, University of Michigan at Ann Arbor - School of Information, MobLab, Chapman University, National Bureau of Economic Research (NBER), California Institute of Technology (Caltech) - Division of the Humanities and Social Sciences, University of Chicago - Department of Sociology, University of Chicago - Booth School of Business, Cornell University - Department of Computer Science, Peking University - Guanghua School of Management, University of Chicago, Massachusetts Institute of Technology (MIT) - Department of Electrical Engineering and Computer Science, Massey University, Independent, Stanford University, Stanford University and University of Minnesota - Twin Cities