Facebook news is selected by editors outside of the site’s algorithm, according to leaked documents released by The Guardian on May 12.
The social media platform, which is now the biggest news distributor in the world, is visited by 1 billion people daily.
The leaked documents come days after former Facebook employees who worked from mid-2014 to December 2015 told Gizmodo that the social media platform, headed by Mark Zuckerberg, routinely suppressed news stories of interest to conservative readers from its “trending” news section.
A journalist who worked for Facebook told Gizmodo that employees averted stories about the right-wing CPAC gathering, politicians Mitt Romney and Rand Paul, and other conservative topics from showing up in the section, even though they were organically trending.
Tom Stocky, Facebook’s VP for search and head of trending topics, hit back quickly, denying the accusations in a statement on May 9.
“We take these reports extremely seriously, and have found no evidence that the anonymous allegations are true,” he said.
Stocky said Facebook has “rigorous guidelines” to “ensure consistency and neutrality.”
But the most recent documents obtained by The Guardian show otherwise. The guidelines for the trending section shows intervention by editors at almost every stage of Facebook’s trending news operation. The team for trending news was once a group of as few as 12 people.
The documents show a section of the guidelines titled “Injecting Topics,” in which a team of news editors working in shifts were instructed on how to “inject” topics into the trending module. Another section of the guidelines was dedicated to blacklisting topics for up to a day.
Documents also show the social media platform turns to only 10 news sources to determine whether a story is trending.
“We measure this by checking if it is leading at least 5 of the following 10 news websites: BBC News, CNN, Fox News, The Guardian, NBC News, The New York Times, USA Today, The Wall Street Journal, Washington Post, Yahoo News, or Yahoo,” the guidelines state.
The documents suggest that the social media giant handles news just like legacy news organizations, with a style guide similar to the Associated Press.
Meanwhile, a U.S. Senate committee sent a letter to Zuckerberg on May 10 demanding answers.
In the letter, the Senate Committee on Commerce, Science, and Transportation asked Zuckerberg if his news curators practiced “politically motivated manipulation.”
Zuckerberg, released a statement on his Facebook page on May 12 saying Facebook is conducting a full investigation into accusations of political bias.
“We take this report very seriously and are conducting a full investigation to ensure our teams upheld the integrity of this product,” he said.
“We have found no evidence that this report is true. If we find anything against our principles, you have my commitment that we will take additional steps to address it,” added Zuckerberg.
Facebook also released the full list of around 1,000 websites it uses to determine trending news on May 13.