New Research: Negative Political Ads Work ... Sometimes; Emory Expert

Contact: MItch Leff, (404) 861-4769,

What: This year, negative political ads have dominated the airwaves. And now a new study by researchers at Emory’s Goizueta Business School has determined why these ads are so effective and what it takes for candidates to get the vote.


It seems that while voters may claim to be irritated by these ads, negative advertising from a candidate or a candidate’s campaign is much more effective than positive ads in getting the vote.



  • Michael Lewis, Associate Professor of Marketing, Goizueta Business School, Emory University
  • David Schweidel, Associate Professor of Marketing, Goizueta Business School, Emory University


Key Points:

  • Negative advertising is a powerful influence in voter preferences and turn out -- but not all political ads are created equal.
  • The research showed negative ads from the candidate or the candidate’s campaign were more effective than negative ads from the PAC (political action committee).
  • Advertising sponsored by PACs was found to be much less effective in terms of two-party vote shares and ineffective in terms of voter turnout.
  • The credibility of the person or group behind the ad may be the determining factor on the effectiveness of the advertising.


More Details


“We find that negative advertising gross rating points (GRPs) from candidates are approximately twice as effective in advertising GRPs sponsored by PACs,” said Michael Lewis, Professor of Marketing at Emory University’s Goizueta School of Business. “In terms of mobilizing voters, we find that negative advertising GRPs from candidates have a significant effect on voter turnout, but negative advertising from PACs is ineffective in mobilizing turnouts.”

David Schweidel, Professor of Marketing at Goizueta, says, “We believe that the pattern of results in our study is due to differences in source credibility across the various ad sponsors and that advertising by PACs may lack credibility.”

The full study:


Process: The study looked at political advertising and its impact on voting in two party races in the 2010 and 2012 U.S. senatorial campaigns.



  • Researched advertising in several designated marketing areas (DMAs), where there were different levels of exposure to the political ads.
  • Looked at advertising discontinuities along DMA boards within states to research the impact of political advertising based on the source of the advertising and the tone of the message.
  • Used gross rating points (GRPs) to measure effectiveness