Facebook wants to set the record straight on its editorial policies so the topic will stop trending on the social network.
The Menlo Park, California, company on Thursday made public its most current Trending Topics guidelines, part of an effort to combat reports that it's politically biased. A 28-page internal document offered a glimpse at how Facebook chooses material that appears in its popular news box.
In the guidelines, Facebook details 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 CNN and Fox News Channel.
"If [a story] is, the topic is given an importance level that may make the topic more likely to be seen," Justin Osofsky, Facebook's vice president of global operations, wrote in a blog post.
The process Facebook uses to determine its Trending Topics gained national attention earlier this week after the tech blog Gizmodo reported that Facebook "news curators" had been told to suppress stories from conservative news outlets so its more than 1.65 billion monthly users wouldn't see them.
The report triggered a reaction from Republicans, with some asking for a Congressional investigation into the social network's practices. The social network, meanwhile, is conducting its own probe into the matter.
"We have found no evidence that this report is true," Facebook CEO Mark Zuckerberg said in a blog post Thursday. "If we find anything against our principles, you have my commitment that we will take additional steps to address it."
Facebook released its guidelines after The Guardian posted internal documents Thursday describing the social network's policies. Facebook told CNET that those guidelines weren't its current parameters.
In a statement to CNET, Osofsky said the social network relies on more than 1,000 sources of news "to help verify and characterize world events and what people are talking about."
He denied claims that Facebook has been biased.
"The guidelines demonstrate that we have a series of checks and balances in place to help surface the most popular stories, regardless of where they fall on the ideological spectrum," Osofsky wrote in the blog post. "Facebook does not allow or advise our reviewers to discriminate against sources of any political origin, period."
Republican Sen. John Thune of South Dakota, who chairs a committee that oversees technology and Internet issues, earlier this week encouraged Congress to look into Facebook's practices. In a terse statement, Thune said, "It is beyond disturbing to learn that this power is being used to silence viewpoints and stories that don't fit someone else's agenda."
Zuckerberg said that "in the coming weeks" he would invite "leading conservatives and people from across the political spectrum to talk with me about this and share their points of view."
The furor over Facebook's editorial policies comes as the company gains more control over our news consumption. Social media now trails only television as a source of news, according to a Nielsen study released this week.
CNET's Shara Tibken contributed to this report.