NEW YORK — John McCain may long for the days when Barack Obama got the lion's share of the media attention: Coverage of the Republican candidate has been overwhelmingly negative news since the conventions ended, a study released yesterday found.

The Project for Excellence in Journalism's report illustrates how the media echo chamber can send things spiraling out of a candidate's control. It's likely to give ammunition to people who say the press has been biased against McCain, but the organization said its findings on that were inconclusive.

"It's quite possible for there to be elements of enthusiasm for one candidate or another," said Tom Rosenstiel, director of the Washington-based think tank. "That's a failure of professionalism if it's there. But this report can't suss it out."

McCain and Obama have received an equal amount of media attention since the conventions. The project judged 57 percent of the stories about McCain to be negative news (including polls showing him falling behind Obama) and 14 percent positive news. The rest were neutral.

Obama's coverage was mixed: 36 percent positive news, 29 percent negative news, 35 percent neutral, the study found.

"I guess it's inevitable, but it does reflect the relentless degree to which winning begets winning," Rosenstiel said. "The polls are so ubiquitous that it is difficult for them not to be the picture frame through which the press views everything."

McCain's poll numbers have been sinking. As a result, many of the stories about him are about why his poll numbers are sinking — and how what he says or does is an attempt to stop his poll numbers from sinking, Rosenstiel said.

The economic crisis, and McCain's response to it, also played poorly for him. His attempt to deflect attention with attacks on Obama and Obama's ties to 1960s radical William Ayers did even worse, the study found. During this time, news organizations also did critical fact-checks on some McCain ads, including one on Obama and sex education that has been widely assessed as inaccurate.

Changes in the media have also heightened the sense of piling on, Rosenstiel said. There are more polls to report on, hence more stories to say McCain is doing poorly in them. The 24-hour news networks are paying a great deal of attention to the campaign because that gets ratings, making for more repeating of stories done elsewhere, he said.

TV networks have been showing off new iPhone-like technology that allows them to pull up maps of the data, and the electoral maps haven't been good for McCain. Financial cutbacks also mean less time for news organizations to do enterprise reporting, again making for more repetition.

Rosenstiel noted that Obama's coverage was largely negative news in the week after the GOP convention, when the surging McCain had the Democrat on his heels and talking about lipstick and pigs.

Sarah Palin has received three times as much press attention as the Democratic vice presidential candidate, Joe Biden, the study found. Her stories were judged 39 percent negative news, 33 percent mixed and 28 percent positive news.

Palin's coverage started out as positive news but turned when reporters went to Alaska to check on her record as governor.

For its study, the Project for Excellence in Journalism looked at some 2,412 stories from 48 news outlets, including newspapers, Web sites and broadcast and cable news. A smaller sample, 857 stories, was used to judge the tone of the coverage.