1. Department of Economics, University of Wisconsin-Madison and NBER pbarwick@wisc.edu
2. S.C. Jonshon College of Business, Cornell University, NBER and RFF sl2448@cornell.edu
3. Department of Economics, School of Business and Management, The Hong Kong University of Science and Technology dyrao@ust.hk
4. Department of Economics, Queen's University nz17@queensu.ca