1. Center for Innovation to Implementation, VA Palo Alto Health Care System , Menlo Park, CA 94025, USA
2. David Geffen School of Medicine, University of California , Los Angeles, CA 90095, USA
3. Quantitative Sciences Unit, Department of Medicine, Stanford University , Stanford, CA 94304, USA
4. Department of Emergency Medicine, University of California , San Francisco, CA 94143, USA
5. Department of Emergency Medicine (Affiliated), Stanford University , Stanford, CA 94304, USA