1. Center for Healthcare Quality and Patient Safety, University of Lugano, Lugano, Switzerland2Center for Surgery and Public Health, Harvard Medical School, Boston, Massachusetts3Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland4Johns Hopkins Surgery Center for Outcomes Research, Johns Hopkins School of Medicine, Baltimore, Maryland
2. Center for Surgery and Public Health, Harvard Medical School, Boston, Massachusetts5Carver College of Medicine, University of Iowa, Iowa City
3. Johns Hopkins Surgery Center for Outcomes Research, Johns Hopkins School of Medicine, Baltimore, Maryland
4. Center for Surgery and Public Health, Harvard Medical School, Boston, Massachusetts3Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland4Johns Hopkins Surgery Center for Outcomes Research, Johns Hopkins School of Medicine, Baltimore, Maryland