The University of Chicago Medicine has earned its 13th consecutive “A” in hospital safety from The Leapfrog Group.

The grade, announced April 24, makes the Hyde Park-based academic health system one of only 49 hospitals in the country to earn 13 sequential top marks since Leapfrog began producing its twice-a-year survey in June 2012. The nonprofit group’s latest survey reviewed data from more than 2,500 hospitals across the country.

The pool of U.S. hospitals to have received the top rating in all consecutive surveys continues to shrink as the number of years under consideration increases: This year, out of more than 2,500 institutions that were surveyed, UChicago Medicine was one of only 49 institutions that earned this consistent A rating. In last fall’s survey, there were 59 hospitals with such a record.

Since 2012, the prominent industry watchdog has evaluated hospital safety twice a year based on 27 publicly available metrics selected and reviewed by a panel of experts. The data range from infection rates, surgical complications and medical errors to safety problems, technology and staffing.

The group then assigns letter grades of “A,” “B,” “C,” “D” and “F” to hospitals, based on the peer-reviewed findings. The results are free to the public and published on Leapfrog’s website.

“Only a very select group of hospitals nationally continue to earn an A Leapfrog Hospital Safety Grade year after year. It shows an unbroken commitment to protecting patients from preventable errors and accidents that harm and even kill too many people in our country every day,” said Leah Binder, president and CEO of The Leapfrog Group.