"Forget liberal bias," says Howard Kurtz at The Daily Beast. New data from a Pew Research study suggests that during the GOP primary season, the media's coverage of presumptive Republican presidential nominee Mitt Romney was twice as favorable as coverage of Barack Obama, undermining the conventional wisdom that the so-called "liberal media" is more lenient on left-leaning politicians. Here, a guide to the findings:

What exactly did the research find?
The study, conducted by the Pew Research Center's Project for Excellence in Journalism, analyzed 52 top newspaper, television, radio, and web outlets from January 2 through April 15. Coverage of Romney was 39 percent positive and 32 percent negative, while Obama's coverage was only 18 percent positive and 34 percent negative. (All other coverage was ruled neutral.) Obama did not have a single week when positive coverage exceeded negative coverage, notes James Crugnale at Mediaite

Why was coverage of Obama so negative?
Republican contenders consistently leveled criticism against him at campaign stops and during debates, and that was often parroted by news outlets. Obama is also "inextricably linked," Kurtz notes, to unfavorable news coverage of the Supreme Court challenge to his health care legislation, rising gas prices, and the struggling economy.  

How did coverage of Romney compare to his GOP rivals?
Romney got a much easier ride, says Pew's Mark Jurkowitz. Rick Santorum "never enjoyed a sustained period of positive press," while Newt Gingrich enjoyed only one week of net positive coverage — the week that he won South Carolina. Ron Paul managed consistently positive coverage, but "this was offset by the fact that the media virtually ignored him," says Kurtz

What else did the study find?
The media called the race in Romney's favor long before the contest was truly over. Romney didn't conclusively nail down the nomination until Santorum suspended his campaign in April, but "the media concluded the race was over Feb. 28 when Romney won the Michigan primary," says Beth Fouhy of the Associated Press. That victory led to a "decisive shift in news media coverage," from a series of skeptical stories to articles that cast Mitt's nomination as essentially secured. There "was a suddenly intense discussion of 'delegate math' and the conclusion that no other candidate could win," says Pew's Tom Rosenstiel. At the same time, coverage of Santorum grew increasingly negative and less frequent. 

Does this disprove "liberal bias" in the media?
Yes, says David Jackson at USA Today. It's time media-bashing conservatives started eating crow. Hold on, says Jonathan S. Tobin at Commentary. Many pundits are spinning this study as proof of "Obama-bashing" in the media, but they've got it wrong. Instead, Obama's "normally adoring press corps covered him more like a candidate than a commander-in-chief," transitioning from fawning over Obama as a historical barrier-buster to scrutinizing him. They were simply subjecting his "poor record" to routine examination. That's not bashing.

Sources: AP, Commentary, Daily Beast, Journalism.org, Mediaite, USA Today