The bad news: The 2012 presidential election is the nastiest in years, with more than 60 percent of the ads that aired in the last three weeks of September aimed at bashing the other guy.

The good news: Some of those nasty ads actually have some substance.

Even as the 2012 presidential race has wallowed in the mire of political insults, this year’s ads have been, for the most part, focused on issues, meaning that if you can dig through the insults and the deceptions, you’ve actually got a shot at learning where both candidates stand.

“It’s not about swift boats, it’s not about birth certificates,” said Shanto Iyengar, director of the political communication laboratory at Stanford University. “It’s about the state of the economy and who has the appropriate skill set and potential to manage the economy.”

During the last three weeks of September, only 7.8 percent of ads aired in the presidential race were positive, mentioning only the candidate they were advertising, according to the Wesleyan Media Project at Wesleyan University, which studies political advertising.

By comparison, in both 2000 and 2008, 30 percent of ads were positive. And in 2004, 19 percent were.

Thirty-two percent of ads have been so-called “contrast” ads that include mentions of both the candidate supported and the candidate opposed.

“The percentage of pure attack ads has sort of gone haywire,” said Erika Fowler, director of the Wesleyan Media Project.

Her analysis found that 63.8 percent of ads aired by Obama and pro-Obama groups were attack ads against Romney. Sixty-one percent of the pro-Romney ads bashed Obama.

But those ads also focused on issues: Nearly every pro-Romney ad mentioned jobs, while almost half of the pro-Obama have have mentioned taxes. And almost half of the pro-Romney spots mention health care. Forty-one percent of pro-Romney spots focus on taxes, meanwhile. In recent weeks, pro-Obama spots have increasingly focused on energy issues, while pro-Romney ads are focusing less on energy issues as the campaign nears Election Day.

Fowler said 60 percent of political ads have focused on policy – typically the economy.

“I was surprised by the extent to which both sides were focused on policy,” she said. “The increase in negative includes an increase in substance.”

Ads in every media market in Ohio are dominated by negative ads, according to the Wesleyan study: In Dayton, 66 percent of all presidential ads, including those aired by outside groups, were negative that aired between Sept. 9 and Sept. 30. In Columbus, 73 percent of the ads that aired during that time were negative, while only 31 percent of the ads in the Wheeling, W. Va. market were. That market spills over in eastern Ohio.

One reason campaigns might be opting for negative: They work, according to Joe Valenzano III, a communications professor at the University of Dayton. They do so by giving people quick bits of information to digest.

“It’s really one of the paradoxes of the American public,” he said. “Everyone hates negative advertising but negative advertising has been shown repeatedly to work.”

At the same time, presidential ads have absolutely skyrocketed: In 2008, Democrats and groups supportive of Democrats aired 82,001 ads totaling $37 million between Sept. 9 and Sept. 30. This year, they’ve aired 93,389 totaling $45 million.

Republicans have also pumped more into TV advertising: In 2008, John McCain and Sarah Palin’s campaign and their supporters aired 49,449 ads between Sept. 9 and Sept. 30, worth $22.5 million. This year, Mitt Romney and Paul Ryan and groups supportive of them aired 69,552 ads during that period, worth $43.5 million.

“It’s a firehose,” said Kathleen Hall Jamieson, director of the Annenberg Public Policy Center at the University of Pennsylvania.

The Annenberg Center has also studied ads this year, but they’ve been looking for accuracy, and they haven’t found much: As of Sept. 20, 27.8 percent of the dollars spent on third-party presidential ads alone contained at least one deception.

They call that progress: In June, the center found that 85 percent of the dollars spent on presidential ads bought by 501(c) 4 groups and 57 percent of the presidential ad dollars spent by super PACs and other groups included at least one deception.

Why the improvement? Jamieson said the groups are now aiming for swing voters who are more likely to be turned off by the negative ads that often include deceptions.

“They’re using a softer strategy now,” she said. “More of an, ‘I’m disappointed’ strategy. They’re trying to get the swing voters who are going to be turned off by a hard-hitting approach.”