A group that studied approximately 100 million cases from 5,000 hospitals has named the 50 best hospitals in the U.S.

List: 50 Best Hospitals

HealthGrades.com said that the hospitals in the top 1 percent had a death rate 27 percent lower on average than the national average.

For the rankings, the group looks at clinical results for 27 procedures and conditions. To be named on of the 50 best, the hospitals had to have elite scores every year of the study. Also, they do not ask to be included.

The list includes nationally known names such as Cedars Sinai in Los Angeles and the Mayo Clinic, but also has many lesser-known facilities.

Mortality rates at the hospitals were adjusted for risk of death for the patients.