In January, the American Federation of Teachers agreed to license NewsGuard’s web browser extension to its 1.7 million members. The company, founded by former journalists, awards reliability scores to thousands of websites to help identify fake news. Conservative groups have accused NewsGuard of having an anti-conservative bias. The company has denied the allegations, citing an advisory board that includes Democrats and Republicans.

But a review of NewsGuard’s employee roster shows a leftward tilt among staff members. The group’s deputy general manager volunteered for Hillary Clinton’s 2016 presidential campaign and served as a delegate to the Democratic National Convention, according to the NewsGuard website. One staff analyst volunteered for Obama’s 2012 campaign, and another served on a Democratic political committee in Connecticut. NewsGuard’s general counsel has served on the board of the League of Conservation Voters, a Democrat-aligned environmental group. The lawyer, Cynthia Brill, has also contributed thousands of dollars to Democratic candidates. None of the NewsGuard staffers listed online have worked for Republicans.