Much ado about nothing: Political advertisements don’t really persuade people at all, Yale study finds

While both major US political parties spend billions of dollars bombarding the population with political ads, a new study from Yale University found that the commercials have little to no effect on voters.

The new study found that regardless of the content or audience, TV political ads have little effect on voters, despite their own leanings or the timing of the ads relative to current events. 

“There's an idea that a really good ad, or one delivered in just the right context to a targeted audience, can influence voters, but we found that political ads have consistently small persuasive effects across a range of characteristics,” explained Alexander Coppock, an assistant professor of political science in the Faculty of Arts and Sciences at Yale.

Coppock and his fellow researchers measured the persuasiveness of 49 high-profile advertisements from the 2016 presidential and general election campaign among 34,000 people who volunteered to participate in 59 randomized experiments over the course of 29 weeks. 

The researchers found that positive ads, attack ads, ads in swing states or dyed-through red or blue states had little effect.

Participants were divided into groups and exposed to advertisements, including a placebo car insurance commercial before answering a questionnaire. The political campaign ads were chosen with respect to real-time, ad-buy data and relevant weekly news coverage.

The researchers tested the persuasiveness of attack and promotional ads for Hillary Clinton, Donald Trump, primary candidates like Ted Cruz and Bernie Sanders while also testing ads based on tone, partisanship of audience, proximity to election day, location in which they were viewed and whether the primary or general election was underway. 

Across all variables, the researchers noted only a .05 shift in a candidate's favorability rating on a five-point scale. In other words, small but statistically significant. 

In terms of swaying people's decisions on whom to vote for, however, the effect was a mere 0.007 of a percentage point. In other words, statistically insignificant.

Ultimately there was little to no variability of persuasive effect from person to person, irrespective of the advertisement in question. 

The researchers were quick to caution, however, that political ads are not always ineffective, and can help improve branding and name recognition of a candidate over time. The study did not examine the modern minefield that is political advertising on social media, however. 

Indeed, Facebook announced Thursday that it would bar all new political ads the week before the US presidential election day, among a raft of new measures “to protect the US elections.”

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