WASHINGTON – The ongoing search for scapegoats to explain the surprise result of the presidential election has found a convenient one in the form of fake news.

But it is impossible to tell how much fake news has affected the election results, said Kathleen Jamieson, the director of the University of Pennsylvania’s Annenberg Public Policy Center, which runs the nonprofitwebsite FactCheck.org.

“There isn’t a good way of knowing—we don’t have reliable survey measures that tell us how much of that sort of information voters have access to,” Jamieson said.

Nevertheless, there has been a documented rise in fake news, and experts say Google and Facebook should take steps to shut it down.

Defining fake news is the first step, said UPenn’s Jamieson, who thinks the label has been used far too loosely.

“When I say fake news, I mean those things that are masquerading as a news outlet’s communication with you,” she said. “…When you get something that takes the name of a network, takes ABC and distorts part of the address online, at that point it is pretending it’s news. The pretense is sufficiently real. There’s a sufficient verisimilitude that it’s actually going to fool an attentive viewer.”

For example, fake news site abcnews.com.co, which its creator characterizes as satire, looks like a regular news site, with a facsimile of the ABC News logo on the top, a menu with different categories of stories such as “fashion” and “tech,” and bylines with ABC News after the authors’ names.

In an interview with the Washington Post this month, abcnews.com.co’s creator said he started the site with the intention to ridicule Trump supporters who “look like idiots” for citing a fake news site.  But they didn’t fact-check and continued to spread the fake news. “I think Trump is in the White House because of me,” he said.

Jamieson suggests implementing a category system where the label “fake news” is only applied to sites that have “hijacked the reputation of a reputable news outlet.”

“We ought to call the other stuff something else,” she says.

This includes legitimate news outlets reporting fake news or misinformation due to a lapse in judgement or fact-checking, “misinformed viral content” such as widely circulated tweets with false information, conspiracy theory blogs, satire, and hyperpartisan news.

And all of these different types of misinformation show up on Google and Facebook, experts say.

“Google’s biggest heft is AdSense, because many of these (fake news) sites…depend entirely on AdSense,” said Alexios Mantzarlis, the leader of the Poynter Institute’s International Fact-Checking Network. “Google is the most important but not the sole provider of online ads, so unless there’s some sort of industry-wide boycott on this tide (of fake news), it may be hard to eliminate them all together.”

“The other thing is the reach of these pages must be reduced, and that’s where Facebook comes in,” Mantzarlis said.

A data analysis by BuzzFeed discovered that fake news surged in popularity on Facebook in the last three months of the election campaign, surpassing the audience engagement of news onmainstream media sites.

Using data obtained from analytics company Jumpshot, Mantzarlis discovered fake news and hyperpartisan websites relied on Facebook for the majority of their referrals. The social media site was responsible for 80 percent of unique visitors to two hyperpartisan websites tracked by Jumpshot and 60 percent to abc.news.com.co.

“That combination is where we should be going to, of Facebook acting on reach and Google acting on ads,” Mantzarlis said.

So far Facebook has promised to stop doing business with fake news apps and Google has promised to introduce a policy to take ads off of fake news sites, NPR reported, but neither company has defined what fake news actually is.

Ken Doctor, a news industry analyst and author of “Newsonomics: Twelve New Trends That Will Shape the News You Get,” says Google has kept Google News reliable by adhering to rules of legitimate news sites for the most part. These rules should be applied to Google Search, which has far looser rules about what news sites are reliable, if Google wants to keep being a reliable news source, he said.

But because they work with news companies to address fake news concerns, Google is much farther along than Facebook, he said.

“They (Facebook) have shown themselves to be clueless about their role in the news world,” Doctor said. This is a problem when the site has a “tremendous influence” on users, who spend an average of 50 minutes a day. “What they need to do is follow a similar path as Google and say we can distribute the news, that’s okay, but we’re going to do it in a way that actually gives our readers legitimate news and not nonsense.”

First, Facebook should distinguish news created by news organizations and content created by users on Facebook news feeds, Doctor said.

“I think they should get rid of the term ‘news feed,’ which has totally blurred that line between what’s news and what’s just what we share,” he said. “That’s a fundamental issue.”

Second, Facebook should improve their algorithms to better filter out fake news sites.

“These sites that are consistently fake, whether they’re making stuff up or lying or manipulating, they’re doing it consistently,” he said. “Whenever you do it consistently, it can be followed.”

But Doctor said these fixes will have no effect on people who already distrust mainstream media and intentionally share fake news.

“This is a matter of degree,” he said. “This isn’t a matter of censorship or turning the spigot off.”

“What Facebook has is a moment,” Doctor added. “It can be a player in civics, of saying to people there’s news, and there’s news that comes out of conservative publications, but these are publications that adhere to standards of accuracy. They’ll tell you their opinion, but they won’t make up facts. It takes the guts of a Facebook or Google to say, ‘This organization meets that standard or doesn’t.’”