Paul Singer

USA TODAY

Hillary Clinton has been vastly outspending Donald Trump on campaign ads, but a new survey suggests Trump is getting far more bang for the buck.

In an online survey by the digital marketing firm Fluent, conducted Tuesday, 52% of respondents said they had seen a television ad in support of Clinton in the previous week and 45% said they had seen an ad supporting Trump. While she has a 7% advantage, it's far less than the margin by which she has outspent him.

Clinton's campaign thus far has aired about 105,000 ads, while Trump's campaign thus far has aired about 33,000, said Travis Ridout, co-director the Wesleyan Media Project which tracks political advertising. The group estimated in mid-May that Trump had spent $18.5 million on TV ads while Clinton had spent about $62.6 million.

The narrow lead for Clinton was repeated through a variety of marketing platforms Fluent asked about: Facebook ads, billboards, Twitter ads and so forth, though far fewer users reported seeing ads for either candidate on Twitter and other on-line platforms than on TV.

"People believe they are seeing advertising from Trump in channels where I can't confirm whether or not he has actually run advertising," said Fluent chief marketing officer Jordan Cohen.

The results seem to reflect Trump's total dominance of political news.

"Donald Trump is a media phenomenon relative to his competition like we've never seen," said Michael Cornfield, associate professor of political management at George Washington University. With all the media coverage of Trump, "his tweets are getting viewed by people who have never been on Twitter."

Cornfield also cautions that "when you ask people where they heard something, they are not all that accurate on where they heard or saw it." So respondents to the Fluent survey could simply be attributing to a Trump ad some positive material they saw elsewhere.

Cohen agrees. "With all surveys, regardless of how they are conducted there is going to an element of response bias, or confirmation bias, where people are just reporting what they think they are seeing and hearing and feeling," he said. He notes that 67% of Democrats said they had seen ads supporting Clinton while only 43% of Republicans said they had, suggesting that Republicans could be under-reporting the pro-Clinton ads they have seen or "are just somehow avoiding consuming them."

Fluent surveyed 3,366 registered voters, and the survey has a 1.7% margin of error.