1. Clinical Research, Investigation, and Systems Modeling of Acute Illness Center, Department of Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
2. Statistics Collaborative, Washington, DC
3. Division of Pulmonary and Critical Care Medicine, School of Medicine, University of Washington, Seattle
4. Pulmonary, Critical Care, Allergy, and Sleep Medicine Program, Department of Medicine, University of California, San Francisco
5. Program in Medical Ethics, Department of Medicine, University of California, San Francisco