1. Entrepreneurial Management Unit, Harvard Business School; Department of Economics, Center of Mathematical Sciences and Applications (CMSA), and Center for Research on Computation and Society, Harvard University; and National Bureau of Economic Research
2. Department of Economics and St Catherine’s College, University of Oxford; and Institute for New Economic Thinking (INET), Oxford Martin School, e-mail: alexander.teytelboym@economics.ox.ac.uk
3. Department of Economics and All Souls College, University of Oxford; and Department of Economics, University of California, San Diego, e-mail: vincent.crawford@economics.ox.ac.uk