1. Department of Neonatology, Beth Israel Deaconess Medical Center, Boston, Massachusetts;
2. Department of Pediatrics, Harvard Medical School, Boston, Massachusetts;
3. Vermont Oxford Network, Burlington, Vermont;
4. Department of Pediatrics, The Robert Larner, M.D., College of Medicine, and
5. Department of Mathematics and Statistics, University of Vermont, Burlington, Vermont;
6. Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia; and
7. Department of Pediatrics, Oregon Health and Science University, Portland, Oregon