The small effects of political advertising are small regardless of context, message, sender, or receiver: Evidence from 59 real-time randomized experiments

The small effects of political advertising are small regardless of context, message, sender, or receiver: Evidence from 59 real-time randomized experiments. Alexander Coppock, Seth J. Hill and Lynn Vavreck. Science Advances  Sep 2 2020: Vol. 6, no. 36, eabc4046. DOI: 10.1126/sciadv.abc4046

Abstract: Evidence across social science indicates that average effects of persuasive messages are small. One commonly offered explanation for these small effects is heterogeneity: Persuasion may only work well in specific circumstances. To evaluate heterogeneity, we repeated an experiment weekly in real time using 2016 U.S. presidential election campaign advertisements. We tested 49 political advertisements in 59 unique experiments on 34,000 people. We investigate heterogeneous effects by sender (candidates or groups), receiver (subject partisanship), content (attack or promotional), and context (battleground versus non-battleground, primary versus general election, and early versus late). We find small average effects on candidate favorability and vote. These small effects, however, do not mask substantial heterogeneity even where theory from political science suggests that we should find it. During the primary and general election, in battleground states, for Democrats, Republicans, and Independents, effects are similarly small. Heterogeneity with large offsetting effects is not the source of small average effects.

Check also Persuasive Effects of Presidential Campaign Advertising: Results of 53 Real-time Experiments in 2016. Alexander Coppock, Seth J. Hill and Lynn Vavreck. Prepared for presentation at the 2019 meeting of the American Political Science Association, Washington, D.C., August 23, 2019. https://www.bipartisanalliance.com/2019/10/persuasive-effects-of-presidential.html

And Le Pennec, Caroline, and Vincent Pons. "Vote Choice Formation and the Minimal Effects of TV Debates: Evidence from 61 Elections in 9 OECD Countries." Harvard Business School Working Paper, No. 20-031, September 2019. https://www.bipartisanalliance.com/2019/10/tv-debates-small-effect-in-voters.html

And Testing popular news discourse on the “echo chamber” effect: Does political polarisation occur among those relying on social media as their primary politics news source? Nguyen, A. and Vu, H.T. First Monday, 24 (5), 6. Jun 4 2019. https://www.bipartisanalliance.com/2019/10/testing-popular-news-discourse-on-echo.html

And Right-Wing Populism, Social Media and Echo Chambers in Western Democracies. Shelley Boulianne, Karolina Koc-Michalska, Bruce Bimber. New Media & Society, presented, in review. Sep 2019. https://www.bipartisanalliance.com/2019/10/echo-chambers-usa-overall-we-find-no.html

And Kalla, Joshua and Broockman, David E., The Minimal Persuasive Effects of Campaign Contact in General Elections: Evidence from 49 Field Experiments (September 25, 2017). Forthcoming, American Political Science Review; Stanford University Graduate School of Business Research Paper No. 17-65. American Political Science Review. https://www.bipartisanalliance.com/2017/11/the-best-estimate-of-effects-of.html