Prediction markets offer insight into Kansas primary races in absence of traditional polls

TOPEKA — Where traditional polling has been quiet, online prediction markets ahead of Kansas’ primary election show who is favored to win key races, offering a glimpse into voter behavior hours before polls close.

Polymarket and Kalshi — the two largest platforms where bettors can weigh the likelihood of candidates’ success — show people have wagered almost $800,000 on Kansas primary races.

Across both platforms, people thought Ty Masterson would be the Republican gubernatorial primary winner, Cindy Holscher the Democratic gubernatorial winner, and Adam Hamilton the Democratic winner in the U.S. Senate primary.

Across just those three races, more than $400,000 was wagered on Polymarket and more than $274,000 on Kalshi.

A 2025 study from Vanderbilt University was the first to test whether prediction markets performed better than traditional polling by comparing Polymarket against polling data from the 2024 presidential election. Researchers said they were partially motivated by notable inaccuracies in polling data in recent presidential elections.

Their findings suggested that Polymarket was superior to polling, especially in revealing voter behaviors in swing states. Researchers said the study’s results aligned with the “wisdom of crowds” theory, which asserts that a large group of people often can accurately predict certain outcomes even if they aren’t experts in a given field or close to an issue.

People bet on Kansas primary races to the tune of $378,000 on Kalshi and more than $420,000 on Polymarket as of Monday. The most expensive race on Kalshi was the Republican gubernatorial primary, which held roughly $140,000 in wagers. On Polymarket, bettors wagered most on the Democratic U.S. Senate primary, which had a $175,000 volume on Monday.

Masterson, president of the Kansas Senate, was favored to win the Republican nomination for governor with more than 95% of odds on both markets. Holscher, a state senator from Overland Park, was favored to win the Democratic nomination for governor with around 90% of odds on both markets. That is despite one of her opponents, state Sen. Ethan Corson of Fairway, having Democratic Gov. Laura Kelly’s backing, and her other opponent, Overland Park Mayor Curt Skoog, not appearing as an option to bet on.

A Republican is favored to win the governor’s mansion in November on Polymarket.

Kansas’ U.S. Senate race hasn’t been viewed nationally as a battleground race, and overall, a Republican is still favored to win the seat in November on both markets. But both markets also showed overwhelming favorability for Hamilton, co-founder of the country’s largest United Methodist Church, based in Leawood. He led both markets with more than 96% of odds as the Democratic U.S. Senate nominee in November. The winner of the Democratic primary will face incumbent Republican U.S. Sen. Roger Marshall.

On Polymarket, odds have wavered for the passage of a ballot question that will ask voters whether they want to change the way state Supreme Court justices are selected. It had accrued a $205 volume, and the odds of it passing were failing Monday by a slim margin.

In-person voting ends in Kansas at 7 p.m. Tuesday. The Kansas Secretary of State’s Office reported 176,732 people had voted in advance, either in person or by mail, as of Monday.