1. Division of General Pediatrics,
2. Center for Pediatric Clinical Effectiveness, and
3. Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania;
4. Leonard Davis Institute of Health Economics and
5. Departments of Nursing and
6. Anesthesia and Critical Care Medicine, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania;
7. GfK Healthcare, Blue Bell, Pennsylvania
8. School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, Pennsylvania;