Research suggests that television advertising influences voters, at least to some extent.
Political scientists examining TV ads in the 2016 presidential election found that, on average, ads increased a candidate’s favorability rating only slightly, regardless of content or audience.
In a 2018 paper, Northwestern University researchers studying 2004–2012 presidential campaigns reported “a positive and economically meaningful effect of advertising on candidates' vote shares" at odds with the "conventional wisdom of limited effects."
A 2010 study found a 1,000-ad advantage increased a candidate’s vote share by 0.5 percentage points, a potentially significant advantage in a close election.