A Measure of Media Bias
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In this paper we estimate ADA (Americans for Democratic Action) scores for major media outlets such as the New York Times, USA Today, Fox News' Special Report, and all three network television news shows. Our estimates allow us to answer such questions as “Is the average article in the New York Times more liberal than the average speech by Tom Daschle?” or “Is the average story on Fox News more conservative than the average speech by Bill Frist?” To compute our measure, we count the times that a media outlet cites various think tanks and other policy groups. We compare this with the times that members of Congress cite the same groups in their speeches on the floor of the House and Senate. By comparing the citation patterns we construct an ADA score. As a simplified example, imagine that there were only two think tanks, and suppose that the New York Times cited the first think tank twice as often as the second. Our method asks: What is the typical ADA score of members of Congress who exhibit the same frequency (2:1) in their speeches? This is the score that we would assign to the New York Times. Our results show a strong liberal bias. All of the news outlets except Fox News' Special Report and the Washington Times received a score to the left of the average member of Congress. Consistent with many conservative critics, CBS Evening News and the New York Times received a score far left of center. Outlets such as USA Today, NPR's Morning Edition, NBC's Nightly News and ABC's World News Tonight were moderately left. The most centrist outlets (but still left-leaning) by our measure were the Newshour with Jim Lehrer, CNN's NewsNight with Aaron Brown, and ABC's Good Morning America. Fox News' Special Report, while right of center, was closer to the center than any of the three major networks' evening news broadcasts. All of our findings refer strictly to the news stories of the outlets. That is, we omitted editorials, book reviews, and letters to the editor from our sample.
Department of Economics, 2005