1. The RAND Corporation, 1776 Main Street, PO Box 2138, Santa Monica, CA 90401, USA
2. Veterans Affairs Greater Los Angeles at Sepulveda, 16111 Plummer Street (152), North Hills, CA 91343, USA
3. Department of Medicine and School of Public Health, University of California, Los Angeles, CA 90024, USA
4. Independent Consultant, HealthCare Quality Initiatives, Newton, MA 02459, USA
5. Leeds Institute of Health Sciences, University of Leeds, Leeds LS2 9JT, UK
6. Feinberg School of Medicine, Northwestern University, Arthur J. Rubloff Building 420 East Superior Street, Chicago, IL 60611, USA
7. Veterans Affairs Greater Los Angeles Healthcare System, 11301 Wilshire Boulevard, Los Angeles, CA 90073, USA