New study detects media's liberal tilt

Professors find most media 'significantly to the left of the average U.S. voter'

Dec. 31, 2005

by David Kopel


People argue a lot about whether the national mainstream media is politically biased, but such arguments are often impressionistic. Earlier this month, professors Tim Groseclose of UCLA and Jeffrey Milyo of the University of Missouri published the results of an investigation using rigorous quantitative analysis.

In A Measure of Media Bias,the authors start by examining the ratings of members of Congress, according to Americans for Democratic Action (ADA). Founded in 1947 by liberals such as Hubert Humphrey and Arthur Schlesinger, the ADA is an excellent gauge of mainstream liberal opinion. The average ADA rating for a member of Congress is 50.1, so a person with a 50 percent ADA rating is almost exactly in the middle of the current American political spectrum.

Groseclose and Milyo looked at how often members of Congress cited the 200 leading think tanks and interest groups in their speeches in Congress. Congresspersons with a lower ADA rating were more likely to cite groups such as the Heritage Foundation, the Christian Coalition, and the National Taxpayers Union. Congresspersons with a higher ADA rating were more likely to cite groups such as the Economic Policy Institute and the Children's Defense Fund.

For example, the average ADA score of a congressperson who cites the American Conservative Union is 16 percent. The average ADA score of a congressperson who cites the National Organization for Women is 79 percent.

Notably, the Groseclose and Milyo study did not require anyone to put a label on a think tank - such as whether the Brookings Institution is liberal, moderate, or conservative. (Its congressional citers have a 53 percent average ADA score.) Rather, the study simply observes which groups are cited by which members of Congress.

Next, the researchers and their assistants counted citations to these same groups in the media, and calculated an ADA rating for each media outlet based on the citations. So if a newspaper cited a mix of groups very similar to groups cited by Sen. John Kerry, the newspaper would have the same ADA rating as Kerry: 88 percent.

Two major media outlets were to the right of the American political midpoint: The Washington Times,at 35 percent, and Fox (the nightly news with Brit Hume) at 40 percent.

Three outlets were slightly left, but still close to the center: The NewsHour with Jim Lehrer, CNN NewsNightwith Aaron Brown, and ABC's Good Morning America- all at 56 percent.

The majority of the media clustered in the 60 to 69 range - significantly to the left of the average U.S. voter. These outlets were (in order of increasing leftishness) ABC's World News Tonight,NBC Nightly News, USA Today,the Todayshow, Time, U.S. News & World Report, NPR Morning Edition, Newsweek, CBS Early Show,and The Washington Post.Every one of these outlets was further from the American political midpoint than was Fox News.

At the far left of the major media spectrum were the Los Angeles Times(70), CBS Evening News(74), The New York Times(74), and The Wall Street Journal(85). The ratings were based only on news stories, so the left-leaning opinion pages at the Los Angeles Timesand right-leaning opinion pages at The Wall Street Journalhad no effect.

The authors conclude: "Our results show a strong liberal bias." Even so, most of the media are much more moderate than Congress itself, where the average Democrat has an 84, and the average Republican a 16.

The study, which builds on previous work by Groseclose and Mil- yo, appears in the November issue of The Quarterly Journal of Economics.It is available online at

You can read various critiques of the study, and its previous iterations, on the Internet. The authors address and refute many of these arguments in their paper.

In any case, no critique undermines the relative rankings of the media outlets - that, for example,The New York Timesis much further left than The NewsHour with Jim Lehrer,or that the three major newsweekly magazines are nearly identical ideologically.

The study did not cover all the sources from which the Denver dailies draw their national and international stories. But of the sources which were studied, every source which supplies a significant amount of news content to a Denver paper (New York Times, Washington Post, Los Angeles Times) has a major leftward bias. The finding suggests that the Denver papers could improve their overall balance by including some stories from The Washington Timesor from other sources without such a pronounced leftward tilt.

By the way, my left-leaning counterpart on this column, Jason Salzman, and I calculated our ADA scores based on 2003-2004 Senate votes. I scored a 16 percent, while Jason got a 91. We agree, however, that there are objective standards by which media bias can be judged. That's one reason we often agree with the critiques that the other raises in our columns.


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