Pity the senior citizens in the voting booth Tuesday. Who should they believe about Medicare—the Dems and their surrogates, who say health reform has strengthened the program, or the GOP and its allies, who charge that reform has gutted it? Both sides have cynically exploited Medicare, and anecdotal evidence shows that the fierce onslaught of campaign advertising is having an effect.

The Wall Street Journal went to Wisconsin and looked at the hot race between Democratic Rep. Steve Kagen and his challenger, Reid Ribble. The Journal’s reporters told of one woman who was going to support Kagen because she was “really upset” with the ads attacking him. But they found a retired industrial consultant who complained that a video of Ribble that Kagan used in his ad was incomplete and misleading. “One thing that sticks in my craw is false advertising,” he said. “How are we supposed to know what is true and what is false?”

That is the question, and Campaign Desk is pleased that so many media outlets have tried to answer it by analyzing the ads and reporting their findings. But the quality of their analyses has varied widely. Where the claims were clearly right or wrong, the task was easy. In Indiana, when Republican senatorial candidate Dan Coats announced that his opponent, congressman Brad Ellsworth, “voted with Nancy Pelosi to force seniors into Barack Obama’s government-run health care program,” it was simple for PolitiFact’s truth-o-meter to debunk the claim. Medicare already is a government-run program, and has been since it began in 1965.

In other cases, the analyses have been harder, especially when it came to figuring out who is bankrolling some of the ads in this year’s campaigns. Slate took a good in-depth look at the 60 Plus Association, which calls itself a “nationally recognized conservative alternative to the liberal AARP.” Political reporter David Weigel pointed out that 60 Plus does not have to disclose its donors, but is “dumping $6 million on ads,” raising the question of who’s paying for them.

His piece described an ad the group ran in northeast Pennsylvania attacking Democrat Paul Kanjorski:

‘Washington liberals like Paul Kanjorski have betrayed Pennsylvania seniors,’ said the first man. ‘He voted for Nancy Pelosi’s big government health care plan that costs a trillion dollars,’ said the second, interrupted by the third, who informed viewers that this plan ‘raises taxes and cuts $500 billion from Medicare.’ ‘Seniors could lose their doctors,’ said the first man, bringing it home.

Other ads from 60 Plus also emphasize the $500 billion Medicare cut. Their message is unmistakable: that $500 billion will hurt seniors. The 60 Plus Association pushed its New York ads on its website, where the group’s chairman asserts “The new health legislation cuts $500 billion from Medicare” and notes the cancellation of one Medicare Advantage (MA) plan, which has affected 22,000 seniors as a result.

Sometimes, refuting the ads’ claims often requires answers that are not as short, snappy, or as memorable as the claims themselves, making them hard for readers to grasp. In Pennsylvania, Crossroads GPS, a group connected to Republican strategists Karl Rove and Ed Gillespie, attacked Democrat Joe Sestak, claiming that “Sestak voted to gut Medicare—a $500 billion cut. Reduced benefits for 850,000 Pennsylvania seniors.” The Associated Press examined that one, concluding that the cuts are spread over ten years and slash projected payment increases to hospitals, insurance companies, and other government health programs. “The Congressional Budget Office places the overall costs of Medicare over 10 years at $7.1 trillion, making the reductions required by the new law amount to 7 percent of Medicare costs. Not exactly a ‘gutting,’” said the AP. Not exactly an easily understood refutation for the public, which tends to stumble over numbers. It might have been easier for readers simply to say that the $500 billion is a small percentage—7 percent—of Medicare’s total budget. The AP also missed the fact that there are spending increases that the law provided for, as well.

Trudy Lieberman is a fellow at the Center for Advancing Health and a longtime contributing editor to the Columbia Journalism Review. She is the lead writer for The Second Opinion, CJR’s healthcare desk, which is part of our United States Project on the coverage of politics and policy. Follow her on Twitter @Trudy_Lieberman.