U.S. Sen. Susan Collins has been named the most bipartisan member of the Senate for the seventh year in a row by the Georgetown University and the Lugar Center, based on a voting index compiled by the two organizations.

Collins, a Republican seeking her fifth term, is in what is expected to be her toughest reelection campaign to date in a race that’s been a focal point for Democrats trying to regain control of the upper body of Congress.

The annual study released Tuesday by the Lugar Center and The McCourt School of Public Policy at Georgetown University uses a methodology that includes two key criteria: –

• The frequency with which a member sponsors bills co-sponsored by at least one member of the opposing party

• The frequency with which a member co-sponsors bills introduced by members of the opposite party.

“I have long believed that Congress produces the best legislation when it incorporates the ideas of both Republicans and Democrats,” Collins said in a prepared statement. “That spirit of bipartisan cooperation is needed now more than ever to confront the unprecedented crisis facing our nation.”