Prediction Markets Sway Voters, According to Brennan Center Study

With Election Day two weeks away, voters are being inundated with polling information and prediction market data is increasingly part of that landscape, but voters don’t like that.

Moreover, a new study by the Brennan Center for Justice indicates that prediction markets’ political event contract data shape voters’ view in fashion comparable to traditional polling. The study also found that more than 80% of respondents want tighter regulations on political derivatives or for those event contracts to be banned outright. Part of the problem is many voters don’t realize the stark differences between a standard poll and prediction market trading activity.

Concerns about prediction markets possibly skewing voters’ views are heightened at a time when more yes/no exchanges partner with legacy media entities, including online, print and television outlets that many Americans turn to for political news.

Yes, Prediction Markets Influence Voters

There’s plenty of doubt regarding the accuracy of political prediction markets. The Brennan Center points out that just 20% of respondents to its study view these markets as accurate while just a third view election-based event contract as representative of the broad public’s views. Still, these derivatives hold some leverage over voters.

“If a candidate was favored by prediction markets, voters were between 10 and 20 percentage points more likely to believe that the candidate would win, regardless of what the polls said,” according to Brennan.

Potentially, that’s a concerning data point at a time when there’s increasing talk that even traditional polls are used as “voter suppression” tools, implying the polls are biased and showing one candidate leading by wide margins in a ploy to keep the other candidate’s supporters away from the polls.

However, there are instances of predictions getting it right with major elections, including the 2024 presidential election. Likewise, major all-or-nothing exchanges showed Assemblyman Zohran Mamdani cruising to victory in advance of Election Day in the 2025 New York City mayoral election.

Power of Dissuasion

While polls and prediction market odds may compel some voters to get involved, those data points can also have the opposite effect, thus acting as voter suppression avenues.

“Prediction market odds can also dissuade voters from believing in a candidate’s electability. Voters were 11 percentage points less likely to say a candidate with 33 percent odds (on a leading prediction market) would win and 19 percentage points less likely to say a candidate with 16 percent odds would win,” according to the Brennan Center. “Prediction market odds had a similar effect on perceived electability as traditional polls, and a stronger effect than any of the candidates’ background traits, including demographics, occupation, or previous experience.”

Twenty-three percent of respondents told Brennan they believe some segments of prediction markets should be halted while 16% said the industry should be completely banned.