How Much Ideological Segregation Is There in Online News Consumption?

By Matthew Gentzkow

Posted on April 9, 2014


How does the internet affect the likelihood of citizens being exposed to information that may contradict their existing views? As news consumption increasingly moves online, the answer to this question has important ramifications for politics. Guaranteeing exposure to information from diverse viewpoints has long been a central goal of media policy in the United States and elsewhere.

The answer is by no means obvious: while internet access makes it easier to read a wide range of opinions, it is also easier for people to ‘self-segregate’ themselves ideologically. Many US commentators believe that what has emerged is the latter outcome - a series of ‘echo chambers’ in which like only listen to like.

Cass Sunstein for example, says that ‘People sort themselves into innumerable homogenous groups, which often results in amplifying their pre-existing views. Liberals reading mostly or only liberals; conservatives, conservatives; Neo-Nazis, Neo-Nazis.’ He concludes that this leads to a reduction in the ‘unplanned, unanticipated encounters that are central to democracy itself.’

In research with my colleague Jesse Shapiro, we measure the degree of ideological segregation in the market for online news and compare it with other news sources. Analyzing data on the news consumption habits of a panel of internet users, we define for each news outlet the share of users who report their political outlook as ‘conservative’ among those who report being either ‘conservative’ or ‘liberal’.

We then define each individual’s conservative exposure as the average share of conservative users on the outlets she visits. For example, if all she visits is the New York Times, her exposure is defined as the share of conservative users on that site. If she visits both the New York Times and Fox News, her exposure is the average of the share of conservative users on those two sites.

Next, we define the isolation index as the difference in the average conservative exposure of conservatives minus the average conservative exposure of liberals. If conservatives only visit Fox News and liberals only visit the New York Times, the isolation index will be 100. If both conservatives and liberals get all their news from CNN’s site, the two groups will have the same conservative exposure and the isolation index will be zero.

Our results indicate that the degree to which liberals and conservatives are isolated from each other’s opinions is low in absolute terms. The average internet news consumer’s exposure to conservatives is 57%. The average conservative’s exposure is 60.6%, similar to a person who gets all her news from USA Today. The average liberal’s exposure is 53.1%, similar to a person who gets all her news from CNN.

News consumers with extremely high or low exposure are rare. Although many people go to sites with ideologically tilted audiences, such as Fox News or the Huffington Post, these are typically part of a news diet with heavy doses of more moderate sites. A consumer who got news exclusively from the New York Times would have a more liberal news diet than 95% of internet news users, and a consumer who got news exclusively from Fox News would have a more conservative news diet than 99% of internet news users.

Nevertheless, the segregation of online news is higher than for some other media: the isolation index for the internet is 7.5 percentage points, which compares with 1.8 for broadcast television news, 3.3 for cable television news, 4.7 for magazines and 4.8 for local newspapers. But the segregation of online news is lower than national newspapers, for which the index is 10.4. We estimate that eliminating the internet would reduce the ideological segregation of news and opinion consumption across all media from 5.1 to 4.1.

Further analysis indicates that on the demand side, these key facts do not require correlation between taste for news and ideology, nor explicit taste for balance among news consumers. On the supply side, there are strong incentives for high-quality news sites to locate closer to the ideological center - but the more that the advertising market values exclusive readers, the stronger the incentives to differentiate ideologically.

Read more from Professors Matthew Gentzkow and Jesse Shapiro’s research on ideological segregation in online news:

The preceding post is republished on TAP with permission by the Toulouse Network for Information Technology (TNIT). “How Much Ideological Segregation Is There In Online News Consumption?” was originally published in TNIT’s March newsletter.