1. Center for Emergency Care Policy and Research, Department of Emergency Medicine (A.S.K., R.M.M., Z.F.M.), Wharton School, University of Pennsylvania Philadelphia.
2. Penn Cardiovascular Outcomes, Quality, and Evaluative Research Center (A.S.K., R.M.M., P.W.G.), Wharton School, University of Pennsylvania Philadelphia.
3. Perelman School of Medicine, and Leonard Davis Institute of Health Economics (A.S.K., R.M.M., P.W.G., A.M., Z.F.M.), Wharton School, University of Pennsylvania Philadelphia.
4. Department of Population Health, NYU Grossman School of Medicine (N.I.), New York, New York
5. Department of Epidemiology, T.H. Chan School of Public Health, Harvard University Boston, Massachusetts (M.L.).
6. Department of Biostatistics, Epidemiology, and Informatics (N.M.), Wharton School, University of Pennsylvania Philadelphia.