How Accurate Are Prediction Markets? The Evidence
'Are they actually right?' is the first question everyone asks about prediction markets. The short answer: yes, more often than the alternatives — but with important caveats.
The Calibration Test
A market is 'well calibrated' if events priced at 30% happen about 30% of the time across a large sample. Studies on Polymarket, PredictIt and the Iowa Electronic Markets consistently show calibration within a few percentage points of perfect, especially on liquid markets with more than a few days of trading history.
Where They Beat Alternatives
Compared to polls, prediction markets react faster to new information. Compared to pundits, they are less biased by narrative. Compared to internal forecasts (say, a company estimating its own product launch date), they are less politically distorted because outsiders with money have no incentive to shade the answer.
Where They Struggle
Thin markets, edge-case resolution rules, and short-lived pump-and-dump attempts can produce distorted prices for hours or days. Always check volume and read the resolution criteria before treating a price as gospel.