Endorsement effects: Are voters influenced by newspaper picks?

The researchers take into account that newspapers are potentially biased in favor of one of the candidates and found that voters rationally account for the credibility of any endorsement. That is, endorsements for the Democratic candidate from left-leaning newspapers are less influential than endorsements from neutral or right-leaning newspapers and likewise for endorsements for the Republican candidate. Knight said these results "suggest that voters are sophisticated and attempt to filter out any bias in media coverage of politics."

To estimate the influence of newspaper endorsements, the researchers used individual-level data on voting intentions and newspaper readership in the months leading up to the 2000 and 2004 elections. They measured endorsement credibility based on the ideological leanings of newspapers, ownership, and reader preferences.

To provide a sense of the magnitude of endorsement effects, Knight and Chiang feature a data table that shows the estimated influence in the top 20 newspapers during the 2000 presidential campaign. They show the least credible endorsements were for Al Gore from The New York Times and for George W. Bush from the Dallas Morning News, which convinced less than 1 percent of their readers to switch allegiance to the endorsed candidate. By contrast, the endorsement with the largest effect came from the Chicago Sun Times, which was predicted to endorse Gore with a probability of 58 percent, but instead endorsed Bush. This endorsement convinced about 3 percent of readers to switch allegiance from Gore to Bush, according to the findings.

These findings are particularly interesting considering the 2008 presidential endorsements. According to Editor and Publisher Magazine, more than 27 newspapers that backed George W. Bush in 2004 have endorsed Obama this year (as of Oct. 22), including large papers such as theDenver Post, Chicago Tribune and New York's Daily News.

"We expect these Obama endorsements to be particularly influential since they have more credibility than endorsements from newspapers that always support the Democrat," said Knight, associate professor of economics and public policy.

Source: Brown University