In the run-up to any election, two numbers compete for your attention: the polls and the prediction markets. They are easy to confuse, but they are fundamentally different instruments. Understanding the difference helps you read both more intelligently.
What each one measures
A poll asks a sample of people what they think or how they intend to vote, then reports the result as a percentage — a snapshot of stated opinion at a moment in time. A prediction market reports the price at which people are willing to trade a contract on the outcome, which behaves as a probability. A poll might say “48% support Candidate A”; a market says “Candidate A has a 63% chance of winning.” Those are different questions: vote share versus probability of victory.
The key differences
- Continuous vs periodic. Markets update every second as news breaks; polls are snapshots taken days or weeks apart.
- Probability vs share. A market gives the chance of an outcome; a poll gives a level of support, which still has to be translated into a probability.
- Incentivised vs stated. Market participants risk money, so they are motivated to be right rather than to express a preference. Poll respondents have no such stake.
- Forward-looking vs current. A good market prices in everything traders expect to happen, including how a race is likely to move; a poll captures only the present.
- Different biases. Polls can suffer sampling and response bias; markets can suffer thin liquidity and trader bias. Neither is bias-free.
When to trust which
Polls are the better tool for understanding why something is happening — which groups support what, and how opinion is shifting. Markets are usually the better tool for the bottom-line question of how likely an outcome is, especially close to the event and when liquidity is deep. When a market is thin, a high-quality polling average may be more reliable; when a market is liquid and active, its probability is hard to beat. For more on the limits, see are prediction markets accurate?
They work best together
This is not really a competition. Markets actually absorb polls: when a major poll lands, traders price it in within minutes. The smartest approach is to use polls to understand the texture of a race and markets to read the live probability — and to treat a large gap between them as a signal worth investigating. To trade these markets yourself, see our guide to political and election markets.
Frequently asked questions
Are prediction markets or polls more accurate?
For the probability of an outcome, liquid prediction markets are often at least as accurate as polling averages and update faster. For understanding the composition of support and why opinion is moving, polls are more informative. They are complementary rather than rivals.
Why do markets and polls sometimes disagree?
They measure different things — probability of victory versus current vote share — and markets are forward-looking, pricing in expected movement that a snapshot poll cannot. A large gap often reflects traders anticipating a shift the polls have not yet caught.
Do prediction markets use polls?
Yes, indirectly. Traders incorporate new polling into prices almost immediately, so a market price already reflects the latest credible polls along with everything else traders know.