1. Operations Research Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142;
2. Indian School of Business, Gachibowli, Hyderabad 50032, India;
3. Sloan School of Management, Massachusetts Institute of Technology, Cambridge, Massachusetts 02142;
4. Riders For Health Malawi, Lilongwe, Malawi;
5. Kellogg School of Management, Evanston, Illinois 60208