1. Department of Emergency Medicine, Los Angeles County-USC, Los Angeles, CA 90033, USA
2. Department of Family Medicine, Boston University School of Medicine, Boston, MA 02118, USA
3. Department of Community Health Sciences, Boston University School of Public Health, Boston, MA 02118, USA
4. Department of Health Policy and Management, Boston University School of Public Health, Boston, MA 02118, USA
5. Center for Healthcare Organization and Implementation Research, ENRM Veterans Affairs Hospital, Bedford, MA 01730, USA