The Leapfrog Group, a nonprofit founded by employers and health-care providers, announced its spring 2016 hospital safety rankings Monday, a measure of how safe a hospital is for patients. Hospitals were given a letter grade from A through F based on several factors. Of the 2,571 hospitals studied nationwide, 798 earned an A, 639 earned a B, 957 earned a C, 162 earned a D and 15 earned an F. At the state level, New York was ranked 44th in the nation. Vermont was ranked No. 1; six hospitals in the state were ranked, and five were given an A grade. Maine, Rhode Island, Massachusetts and Minnesota rounded out the top five.

State rankings were based on a percentage of state hospitals receiving an A grade. Leapfrog looked at medical errors, accidents, injuries and infections to determine the grades. The goal was to determine a patient's risk of further injury or infection if they visited a certain hospital. Hospitals given a B rating by Leapfrog had a 9 percent higher risk of avoidable death than A hospitals. That number jumps to 35 percent in C hospitals and 50 percent higher in D and F hospitals. Leapfrog ranked 143 New York hospitals. Here are the grades Long Island hospitals received. (Visit the full list to learn more about individual rankings.) A John T. Mather Memorial Hospital, Port Jefferson

Huntington Hospital, Huntington

St. Francis Hospital of Roslyn, Roslyn B Eastern Long Island Hospital, Greenport

Mercy Medical Center, Rockville Centre

South Nassau Communities Hospital, Oceanside

Southampton Hospital, Southampton

St. Catherine of Siena Medical Center, Smithtown

St. Charles Hospital, Port Jefferson

Winthrop-University Hospital, Mineola C Good Samaritan Hospital Medical Center, West Islip

Nassau University Medical Center, East Meadow

North Shore University Hospital, Manhasset

Long Island Jewish Medical Center, New Hyde Park

Franklin Hospital, Valley Stream

Glen Cove Hospital, Glen Cove

Plainview Hospital, Plainview

Syosset Hospital, Syosset

St. Joseph Hospital, Bethpage D