1. Department of Emergency Medicine, Yale University School of Medicine, 464 Congress Ave, Ste 260, New Haven, CT 06519.
2. Center for Outcomes Research and Evaluation, Yale University School of Medicine, New Haven, CT.
3. Department of Economics, Dartmouth University, Hanover, NH.
4. Department of Economics, Yale School of Management, New Haven, CT.
5. Department of Emergency Medicine, Massachusetts General Hospital, Boston, MA.