Facebook has made public its internal editorial guidelines, in the latest attempt to fight charges of political bias in the news stories it promotes to its 1.6 billion users.
Technology news website Gizmodo on Monday reported that a former Facebook employee said workers "routinely suppressed news stories of interest to conservative readers," while "artificially" adding other stories to the trending list.
A 28-page internal document offers details on how Facebook chooses material that appears in its popular news box. It shows how a combination of computer algorithms and human editors determine what should be a trending topic on a Facebook page. Algorithms first detect stories that are being widely shared on the platform, then human editors cross-reference the stories to see if they're being covered by 10 major news outlets, including The New York Times, CNN, BuzzFeed and Fox News Channel.
Stories covered by those outlets gain an importance level that may make them more likely to be seen.
Justin Osofsky, vice president of global operations, said the guidelines ensure that stories in trending topics represent "the most important popular stories, regardless of where they fall on the ideological spectrum.''
The Gizmodo report triggered a reaction on social media, with several journalists and commentators raising concerns about alleged bias, and Republicans calling for a congressional investigation.
Republican Senator John Thune, chairman of the Committee on Commerce, Science and Transportation, said Tuesday that Facebook needed to respond to "these serious allegations."
