Massachusetts General tops U.S. News & World Report's  2012 list of the best U.S. hospitals, knocking Johns Hopkins out of the top spot it's held for 21 years.

The rankings, produced by RTI International, are based on several factors:

• Patient survival. On a 1-to-10 scale, this score accounts for 32.5% of a hospital's ranking.
• Reputation. Two hundred doctors in each specialty are randomly selected and asked to list the hospitals they think are best in their specialty for complex or difficult cases. This accounts for 32.5% of a hospital's ranking.
• Patient safety score. Hospitals are rated on how well they work to prevent the worst kinds of harmful blunders. This accounts for 5% of a hospital's ranking.
• Other factors. Care-related factors such as nurse staffing, technology, and other factors linked to quality care account for 30% of a hospital's ranking.

This year, 17 hospitals made the list's honor role. These are hospitals that score at or near the top in at least six of the 16 specialties considered in the ratings.

The honor roll:

1. Massachusetts General Hospital, Boston
2. Johns Hopkins Hospital, Baltimore
3. Mayo Clinic, Rochester, Minn.
4. Cleveland Clinic
5. Ronald Reagan UCLA Medical Center, Los Angeles
6. Barnes-Jewish Hospital/Washington University, St. Louis
7. New York Presbyterian University Hospital of Columbia and Cornell, N.Y.
8. Duke University Medical Center, Durham, N.C.
9. Brigham and Women's Hospital, Boston
10. UMPC University of Pittsburgh Medical Center
11. NYU Langone Medical Center, New York
12. Northwestern Memorial Hospital, Chicago
13. UCSF Medical Center, San Francisco
14. Mount Sinai Medical Center, New York
15. Hospital of the University of Pennsylvania, Philadelphia
16. Indiana University Health, Indianapolis
17. University of Michigan Hospitals and Health Centers, Ann Arbor

The ratings also listed the best hospitals for major medical specialties. The winners in each category:

• Cancer: University of Texas M.D. Anderson Cancer Center, Houston
• Cardiology and Heart Surgery: Cleveland Clinic
• Diabetes and Endocrinology: Mayo Clinic
• Ear, Nose, and Throat: Johns Hopkins Hospital
• Gastroenterology: Mayo Clinic
• Geriatrics: Johns Hopkins Hospital
• Gynecology: Mayo Clinic
• Nephrology: Cleveland Clinic
• Neurology and Neurosurgery: Johns Hopkins Hospital
• Ophthalmology: Bascom Palmer Eye Institute at the University of Miami
• Orthopedics: Hospital for Special Surgery, New York
• Psychiatry: Johns Hopkins Hospital
• Pulmonology: National Jewish Health, Denver-University of Colorado Hospital
• Rehabilitation: Rehabilitation Institute of Chicago
• Rheumatology: Johns Hopkins Hospital
• Urology: Cleveland Clinic

SOURCE: U.S. News & World Report web site.

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