That means outside groups are responsible for more than 80 percent of the ads voters have seen this year -- while the candidates have sponsored just 19 percent of the spots.
The remarkable growth in campaign activity by independent groups reflects how politics have been transformed since the Supreme Court's 2010 Citizens United decision, which paved the way for the creation of super PACs. For the first time, nearly every major presidential candidate is being backed by a personalized super PAC, a dynamic that has help drive the volume of ads up 44 percent compared to this point in 2011.
"I think it speaks to just how much big money is going into the nomination race nowadays," said Travis Ridout, a co-director of the project.
But the deluge of TV spots does not appear to be shaping the views of GOP voters assessing the crowded field-- at least not yet. In fact, there appears to be an inverse correlation to the number of ads run for a candidate and his or her poll standing. Former Florida governor Jeb Bush, who garnered just 5 percent in the latest Washington Post-ABC poll, has had 15,750 ads run on his behalf by his campaign and allied super PAC from Jan. 1 through Dec. 9. But there have been no ads run for Donald Trump, who hit a high of 38 percent in the poll and has benefited from nonstop media coverage. And 457 spots have aired in support of Sen. Ted Cruz of Texas, who placed second in the Post-ABC poll, with 15 percent.
So far, all the commercials on the Democratic side have been run by the candidates themselves, with Hillary Clinton airing nearly double the number of ads as Sen. Bernie Sanders of Vermont, the study found.
The biggest ad sponsor on the Republican side has been Right to Right USA, a super PAC supporting Bush that has run 15,220 spots. The second largest: Conservative Solutions Project, a tax-exempt "social welfare" group that does not reveal its donors. The organization has run 4,882 commercials advocating for Sen. Marco Rubio of Florida, Wesleyan found. That makes Rubio the only candidate so far that has benefited to such an extent from a nonprofit that keeps its donors secret. The group has a sister super PAC with a similar name that is now running its own ads touting Rubio.
The heavy reliance of GOP candidates on their outside allies for air support means that Republicans are spending far more on TV than Democrats, as candidates are charged a much lower rate for air time. So while Bush and his allies have shelled out an estimated $25.7 million to air 15,750 national broadcast and cable ads, Clinton's campaign has spent an estimated $8.2 million to run 13,450.
Anu Narayanswamy contributed to this report.