Can Prediction Market Odds Offer Better Political Insight Than Traditional Polls?
Washington County election director Melanie Ostrander expected turnout to reach roughly 78% in November 2024. Across Pennsylvania, polling still offered little certainty about which presidential candidate those voters would send to the White House.
Prediction markets appeared more decisive. Their prices favoured Donald Trump, although the confidence behind them varied sharply between exchanges. Polls and market prices may both be displayed as percentages, but they measure different things.
Pennsylvania Gave Both Methods A Serious Test
The presidential campaigns treated Pennsylvania as essential. Candidates made repeated visits, advertising dominated local television and election departments prepared for a busy day. The state’s importance was especially familiar in southwestern Pennsylvania, where officials discussed expected turnout as the Keystone State again occupied a decisive place in the contest.
Late polling reinforced the sense that the result could go either way. Some averages showed a tie; others gave Trump a lead of less than one percentage point. The count was close, though not quite as close as polling suggested. Pennsylvania’s official election returns recorded 50.37% for Trump and 48.66% for Kamala Harris, producing a winning margin of 1.71 percentage points.
The polls slightly understated Trump’s advantage, yet they still described Pennsylvania accurately as competitive. Pollsters were trying to measure support across millions of voters, accounting for turnout, undecided respondents and the difficulty of assembling a representative sample. A winner contract faced a simpler test. It paid according to which candidate won, whether the margin was 20 points or a few thousand votes.
Reading Political Prices Like Betting Odds
Consider two figures that could have appeared beside Trump’s name before Election Day: 48% in a poll and a 60-cent price on a prediction exchange. The first would represent the share of surveyed voters who said they supported him. Because a successful contract typically settles at $1, the second would imply that traders collectively gave Trump about a 60% chance of winning. It would say nothing about his expected share of the vote.
Anyone accustomed to reading sports odds will recognise the principle. Odds express an implied probability rather than a promise about the final result. They may also move when new information arrives or more money enters the market. Political contracts apply that familiar logic to elections instead of games.
Traders might weigh published polls against early-voting data, economic releases, campaign news and the possibility of another polling error. Prices may react almost immediately. Conventional polling takes longer because researchers must conduct interviews, weight the responses and prepare the findings for publication. In return, it provides direct evidence of voters’ stated intentions. A market price records the judgement of those choosing to trade. For a newsroom examining why a county is shifting, polling may reveal more. For someone asking only who is likely to win, the market offers the simpler figure.
Election-Eve Prices Told Different Stories
There was no single market verdict in 2024. On 4 November, Reuters reported that Polymarket priced Trump at about 57% and Harris at 43%. Kalshi’s traders were less certain, putting the contest at 51% to 49%. Both exchanges selected the eventual winner, but their probabilities described noticeably different races.
The activity behind those prices differed too. Reuters placed overall trading associated with Polymarket’s presidential market at approximately $3.1 billion, although about $1.97 billion concerned the direct Trump-or-Harris winner contracts. Kalshi’s election-outcome contract had attracted nearly $197 million.
A 2025 Vanderbilt preprint later compared Polymarket with aggregated polling during the election. The researchers found that the exchange identified Trump as the likely national winner from around 18 October and favoured him in five of the seven battleground states, including Pennsylvania. By that winner-picking measure, Polymarket performed better.
Broader research produced a less uniform result. A separate Vanderbilt working paper examined more than 2,500 political contracts and approximately $2.4 billion in transactions across four exchanges during the campaign’s final five weeks. PredictIt contracts forecast outcomes better than chance in 93% of cases, compared with 78% for Kalshi and 67% for Polymarket.
Comparable contracts also carried different prices across exchanges, creating arbitrage opportunities that became particularly common during the final two weeks. Even with substantial activity, each platform reached its own assessment according to its participants, rules and available capital.
What Moves A Political Price?
A political contract can look straightforward until its settlement terms are examined. The outcome might depend on the Electoral College, popular vote, control of Congress or a designated organisation formally confirming a winner. A price therefore makes sense only when read alongside the exact event being traded.
Movement needs similar scrutiny. A gradual shift involving numerous trades carries different information from a sudden jump following one large position. The same applies when sports odds move: a change may reflect new information, the weight of incoming money or both. Reuters reported that a French trader had accumulated substantial pro-Trump positions on Polymarket, showing how unevenly capital may be distributed among participants.
Understanding the exchange is part of interpreting its prices. The sports-betting information and analysis site Covers.com explains Kalshi’s account requirements, promotional terms and access process alongside details of how the platform operates. These mechanics show how people enter the market, although the strength of any political price still depends on the contract and trading behind it.
Traders are not intended to form a representative sample of Americans. They choose whether to participate, select the questions that interest them and trade with unequal amounts of money. Pollsters take another approach by constructing and weighting samples to resemble the population being measured.
Sometimes The Gap Matters More Than The Forecast
Polymarket identified the 2024 winner before aggregated polling offered a firm favourite. For a binary question about who would enter the White House, that gives prediction markets a credible result to point to. Polling served another purpose: showing how voters said they intended to vote and how close Pennsylvania remained.
The most informative moments may occur when market prices separate from stable polling. Traders could be accounting for turnout, historical polling errors or developments not yet captured in published surveys. A few large positions or traders following an existing price movement could produce a similar pattern.
The percentage cannot supply that context by itself. Its political value becomes clearer once readers know whether it came from interviewed voters, a statistical model or contracts purchased on an exchange.