News coverage of the U.S. presidential election is noticeably more negative in tone toward Republican candidate John McCain compared to coverage of Democratic candidate Barack Obama, according to a study by the Pew Research Center’s Project for Excellence in Journalism.

A team of researchers coded stories for “tone” during the six weeks between the end of the Republican convention and the final presidential debate. While the amount of coverage was split equally between the two candidates, coverage of McCain was deemed to be 57 per cent negative and only 14 per cent positive (the rest were neutral) while stories about Obama were 36 per cent favourable and only 29 per cent negative.

Although American conservatives may see this as more evidence of “media elite” liberal bias, the study’s authors suggest that’s not it. Since most of the news coverage (53 per cent) focused on horse-race issues like strategy and polling, rather than policy (22 per cent), story tone inevitably tended to favour the horse in the lead.

Winning the Media Campaign: How the Press Reported the 2008 General Election (PDF)