Media Bias

The comments in response to my recent post on Barack Obama’s book led, predictably, to the topic of media bias.

Media bias is one of the hottest topics among economists these days. A sampling of some recent academic work on the topic:

Tim Groseclose and Jeff Milyo estimate how left-wing or right-wing media outlets are based on what research by think tanks they mention in their stories. They then compare that to the think tank research that elected officials cite when they talk on the House or Senate floor to calibrate where the media fits relative to the Congress. They find some interesting answers: most of the media does have a liberal bias (throwing out the editorial page, Wall Street Journal is the most liberal of all, even beating the New York Times!). Fox News is one of the few outlets that is right of center.

My colleagues Matt Gentzkow and Jesse Shapiro measure media bias by finding phrases that Democratic politicians use to describe an issue (“Estate tax” or “War in Iraq”) versus Republicans (“Death Tax” or “War on Terror”), and seeing which ones newspapers use. After building their index, they turn to determining what forces drive the newspapers’ choices. The answer seems to be that the newspapers slant their reporting to what their readership wants to hear, but they see little evidence that who actually owns the newspaper (e.g. Rupert Murdoch) matters for how it reports.

Finally, Alan Gerber, Dean Karlan, and Daniel Bergan run a field experiment to determine whether the content in a newspaper affects what people believe. They give free newspaper subscriptions to people in Northern Virginia. Some get the Washington Post (liberal) others get the Washington Times (conservative). They then poll the people in the experiment to see what their opinions are on political questions. Their results suggest that receiving the newspaper affects how people respond to the survey on a number of issues, especially who they want to be Governor.