Politicians can use social media ads to buy votes for €4 per person
Online political adverts can sway voters
Denis Kornilov/Shutterstock
Political adverts on social media really can increase a candidate’s popularity, according to an analysis of German election results that suggests swaying a single voter requires around €4 of advertising spend.
Dominik Bär at Ludwig Maximilian University of Munich in Germany and his colleagues analysed more than 21,000 Facebook and Instagram adverts posted by German political parties in the run-up to the 2021 federal elections. “We were interested in how these parties are advertising and how it related to the election outcome,” says Bär. The team used Meta’s advert transparency website, which records all political adverts on the firm’s platforms, and found that the posts were viewed a total of 126 million times.
After using a statistical model to account for confounding factors, such as whether the candidate was an incumbent or not and how much time they spent campaigning, the team found that advertising on social media had a positive effect on the likelihood that a candidate won an election.
The researchers were able to quantify the impact of social media campaigns, finding that every 200,000 times their advert was seen, a candidate’s votes increased by 2.1 per cent. “That this happens at this scale was a bit surprising,” says Bär.
Perhaps most importantly, the researchers believe that the results may reflect what happens in other countries where people vote directly for a representative across constituencies. While this is only partially true in the German federal elections, which also include indirect votes through a system of proportional representation, it is similar enough to others, says Bär.
“The election is comparatively large, with more than 60 million eligible voters and candidates from multiple parties across the political spectrum,” he says. “The results may thus generalise to other elections.”
He adds that the findings are even more pertinent this year, which is full of important elections. “I think this is very interesting now, with the US election coming up in November, but then also the European elections,” says Bär.
The researchers looked at how close races were in the 2021 German federal elections and found that the outcome would have changed in 12 out of 299 constituencies if the second-place candidate had received a 2.1 per cent increase in vote share, translating to an average of 500 additional votes. Achieving this swing through online ads would cost around €2000, or €4 per voter. For context, 1785 candidates representing major parties in that election spent a total of around €1.4 million on online political ads.
However, not everyone is as certain about the results. “This is one study and an outlier compared to the large-scale studies,” says Kate Dommett at the University of Sheffield, UK. “I would be cautious about this result.”
Dommett points out that the effect of adverts on votes are of a magnitude greater than previous studies of social media-based advertising campaigns have shown. “In general, most studies of political ads’ effectiveness show small effects, which are notably smaller than the effects of more traditional communications strategies such as doorstep canvassing or volunteer phone calls,” she says.