Study: Ideological bubbles evident in Congress’ news-sharing habits


The partisan political divide around news provider preferences is evident in the way members of Congress share news on their Facebook pages, according to a new study from Pew Research Center.

For the study, Pew researchers put members of Congress on a liberal-to-conservative ideology scale, with -1 being the most liberal to 1 being the most conservative. For example, House Minority Leader Nancy Pelosi (D-Calif.) scored a -0.49 on the scale.

Pew also scored national news outlets based on the scores of lawmakers who shared their articles and how often their articles were shared. Democratic lawmakers shared the New York Times more frequently than Republicans, for example, giving the publication a score of -0.28.

The study then looked at Facebook posts from members of Congress — published between January 2015 and July 2017 — that included links to articles.

Pew Research Center

Links to articles on a number of news sources — like Bloomberg, ABC News, CBS News, Politico, CNN and the Washington Post — were shared by members of both political parties. In particular, congressional Republicans linked to articles from CNN — which President Donald Trump has regularly targeted as so-called “fake news” — 1,062 times, slightly more often than the 1,011 times their Democratic colleagues did.

Other news outlets, like the New York Times and the Huffington Post, were shared more often by liberal lawmakers than by their conservative counterparts. Meanwhile, Republicans linked to articles from Forbes and the Wall Street Journal more frequently than Democrats.

Five percent of national news outlets were shared exclusively by one political party. For example, congressional Republicans shared links to articles from Breitbart, an alt-right publication, nearly 700 times over the course of the study, while Democrats never linked to Breitbart in the same time period.

Lawmakers who shared articles from news outlets their political party predominately shared enjoyed higher post engagement than when they linked to news shared by members of both parties. The same goes for posts linking to more polarizing news outlets.

“When Democrats or Republicans in Congress shared stories from outlets with the most liberal or conservative sharing scores, respectively, the Facebook audience reshared those posts 21% and 22% more often than if the stories came from outlets that fell in the middle of the score’s range,” Pew researchers wrote.

The study also found that since Trump’s inauguration, Democratic members of Congress have doubled the number of Facebook posts linking to national news (from 8% to 16%). Republicans, meanwhile, shared roughly the same amount of news after Trump assumed the presidency that they did before (from 8% to 9%).