Prediction-market odds vs polls: what each signal can and cannot tell you

A poll usually estimates current opinion among a defined population. A prediction market usually asks whether a specified event will happen by a deadline. Poll shares and market probabilities therefore use different units and should not be placed side by side as if they were interchangeable.

For an election, a poll may estimate vote intention today. A winner market incorporates views about polling error, turnout, campaign events, electoral rules, and how much time remains. The market can price one candidate above 50% even when that candidate polls below 50% of the vote.

Differences often come from uncertainty rather than disagreement. A two-point polling lead might translate into a much larger probability of victory if the lead is stable and the electoral system is favourable. The same lead may imply less confidence when polling is sparse, the race is volatile, or the relevant geography differs from the headline sample.

First match the object being measured: national vote, state result, seat count, nomination, or final winner. Then align the dates and check whether either signal is stale. Finally, inspect a time series rather than a single screenshot. Direction and persistence usually tell you more than one isolated value.

When the signals disagree, treat the gap as a research question. Look for structural explanations before deciding that one source is wrong. EventAlpha's event hubs help by placing related contracts together so inconsistencies are easier to spot.

Polls are estimates with sampling and modelling limitations. Prediction markets are prices formed by participants under a specific set of rules. Both can be useful; neither is an oracle. The safest language is probabilistic: what the evidence currently suggests, how strong the signal looks, and what could change it.