Mike Lewis and David Schweidel of Emory University and Yanwen Wang of the University of British Columbia in Vancouver co-authored a study that found negative political adverting is more effective than positive political advertising in senatorial campaigns. The study “A Border Strategy Analysis of Ad Source and Message Tone in Senatorial Campaigns” is published in INFORMS journal Marketing Science.

Professors Lewis, Schweidel and Wang looked at advertising effectiveness in two-party races in the 2010 and 2012 U.S. senatorial elections. The analysis employed a “border strategy” involving a comparison of voting behaviors across demographically similar counties that were exposed to different levels of advertising due to the advertising being sold based on designated market areas, or DMAs. When advertising is targeted based on DMAs, it creates a setting in which neighboring counties may receive different levels of advertising exposure. Under the assumption that neighboring counties tend to be similar markets, these discontinuities create a natural experiment.  The analysis used extensive and detailed data including information on gross rating points (GRP) for every ad in these DMAs, every ad sponsorship and tone, demographics, and county-level votes.

Wang, Lewis and Schweidel found negative advertising is effective in influencing preferences and voter turnout, but not across the board. The ads from candidates had more clout compared to ads from political action committees, or PACs. A reason for this could be the credibility of the person or group behind the ad may be the determining factor on the effectiveness of the ad.

They also found negative advertising GRPs from candidates are approximately twice as effective as advertising GRPs sponsored by PACs. A 1 percent increase in negative advertising by the candidate produces a significant 0.015 percent lift in the candidate’s unconditional vote shares. On the other hand, negative advertising from PACs is ineffective in increasing its supported candidate’s unconditional vote share.

The work shed light on current controversies and concerns related to political advertising. For example, while most voters claim to hate “negative” ads, the research suggests that “negative” ads are more effective than positive ads. Recent history has also seen increased concern about money in politics since Super PAC rules allow for unlimited contributions. The research suggests that money funnel through Super PACs may be less influential because these groups lack credibility. 

Lewis and Marketing Analytics Center’s Ada Chong discuss the paper in the “Fanalytics with Mike Lewis” podcast.