1. Graduate School, Rollins School of Public Health, Emory University, 1518 Clifton Road NE, Room 467, Atlanta, GA 30322, USA
2. Center for Connected Health, Partners Health Care, Boston, MA, USA
3. Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA
4. Emory Rollins School of Public Health and Emory School of Medicine, Atlanta, GA, USA
5. Department of Statistics, Institute of Technology Assessment, Massachusetts General Hospital, Boston, MA, USA