Prediction Markets and Election Forecasting
Election markets turn thousands of individual bets into one running probability. Here's the mechanism behind that number, and why it moves the way it does.
From opinions to a single number
An election prediction market lets anyone buy a contract tied to a candidate or outcome winning. As people trade, the price settles at whatever level currently balances buyers and sellers — which is why it's described as a probability rather than a prediction. It's the market's current best guess, continuously revised as new money and new information arrive, not a fixed forecast set once and left alone.
What actually sets the price
Unlike a poll, which asks a sample of people what they intend to do, a prediction market asks people to back their belief with money — including their view of things a poll can't easily capture, like how enthusiastic each side's voters are, whether turnout will match historical patterns, or how much weight to put on polling itself. That's what makes the price a different kind of signal than a poll average, even when both are trying to answer the same question.
Why the number moves constantly
Debates, court rulings, campaign events, and even other markets' related contracts can all shift the price within minutes. That volatility isn't a flaw — it's the market doing its job, repricing as the information set changes. A probability that hasn't moved in weeks usually means the underlying picture genuinely hasn't changed, not that the market has stopped paying attention.
Why markets and polls can tell different stories
Polls and markets are measuring related but distinct things. A poll captures stated intent among a sampled group at a specific moment; a market captures aggregated belief about the eventual outcome, filtered through everyone's private read on turnout, momentum, and polling error itself. When the race is close, this gap can widen, since small differences in how each method handles uncertainty get amplified.
Reading these markets responsibly
- Probability isn't destiny. A candidate priced at 80% can still lose — that's what an 80% probability means, not a rounding error.
- Liquidity varies by race. National headline races tend to have deep, well-arbitraged markets; down-ballot contracts can be thin and jumpy.
- Not political advice. These prices reflect trader positioning, not an endorsement or forecast anyone should act on.
See how live election-related contracts are pricing on the live dashboard →
Quick answers
How does an election market turn into a single probability?
Every trader who buys or sells a candidate's contract is putting money behind a view, and the resulting price is the point where buyers and sellers currently agree — a continuously updated, capital-weighted average of everyone's belief.
Why do election markets sometimes disagree with polls?
Polls measure stated voter intent at a moment in time. Markets also price in turnout expectations, structural factors like state-by-state dynamics, and how likely people think it is that polls themselves are missing something — so the two can diverge, especially in close races.
Do election prediction markets predict the winner?
No. They estimate a probability based on currently available information, which can and does change as the race develops. A high probability is not a guarantee, and markets have been wrong before.