I Definitely Have to Read This Book

Yesterday we discussed Tim Groseclose’s Fox TV interview in which there seemed to be some confusion about who gets to be a tax-exempt 501( c)(3) group.

This got me curious about the content of Groseclose’s book. Here’s what I found:

Media bias aids Democratic candidates by about 8 to 10 percentage points in a typical election. I [Groseclose] find, for instance, that if media bias didn’t exist, John McCain would have defeated Barack Obama 56 percent to 42 percent, instead of losing 53-46.

Oof!

The above quote is from a columnist named Paul Bedard. I’ve never heard of him before—I found the link through Google—but given that, according to the source, “the Drudge Report is approximately the most fair, balanced, and centrist news outlet in the United States,” I’d guess that Bedard is probably slightly to the left of center.

I was amused to see that, in the quote above, the word “John McCain” was given a hyperlink to a page with this photo:

The following profile begins, “John McCain, a two-time presidential candidate and the senior senator from Arizona, was born in the Panama Canal Zone to a well-known military family. Both his father and grandfather were decorated admirals.”

In contrast, Barack Obama received no link, but appended to the quote was a hyperlink to “[See editorial cartoons about Barack Obama.]”, a page that begins with this clever bit of political satire:

http://themonkeycage.org/wp-content/uploads/2011/07/35.jpg

This seems like liberal bias to me. I’d much rather be portrayed shooting baskets than posing with a tie.

OK, let’s try to apply some statistical methodology here. As we know, the best way to measure the bias of any news organization is to count who they cite. Here’s a quick check of the sources cited by Bedard:

Drudge Report
Fox News
UCLA
ABC
CBS

CNN
NBC
National Public Radio
New York Times
Washington Times

Now let’s code these. I think the most objective approach is to use Groseclose’s estimates. This gives us the following:

left: ABC, CBS, CNN, NBC, National Public Radio, New York Times
right: Fox News, Washington Times
exact center: Drudge Report

And I don’t think anyone will object if I place UCLA on the left.

Bedard mentioned 7 sources on the left, 1 on the right, and 1 in the exact center. Seems pretty liberal to me. Now I don’t know whether to trust him at all!

In all seriousness, I really do want to see the book now to see how the concept of “absolute bias” is defined. As I wrote a few years ago, I thought the Groseclose and Milyo paper was interesting but I couldn’t see how they could claim to get any absolute, rather than relative, measures.

[Cross-posted at The Monkey Cage]

Andrew Gelman

Andrew Gelman is a professor of statistics and political science and director of the Applied Statistics Center at Columbia University.