How Accurate Are Prediction Markets? The Evidence
How accurate are prediction markets? Brier scores, calibration, the Iowa Electronic Markets record, famous misses and the biases that still distort prices.
Arnold Vezcasi
Guides & Research
Arnold Vezcasi
The guides byline: first-trade walkthroughs, the glossary, research on how accurate markets are, and the tools worth using.
4 articles
About Arnold
Arnold Vezcasi is the byline on PredictReport's explainers and reference guides, the pieces the rest of the site leans on: the walkthrough for a first trade, the glossary, the research on how accurate prediction markets really are, and roundups of the tools traders use.
The test for every guide is whether someone with no background can finish it able to read a market, say what a price means and what a trade costs, and decide whether to take part at all. Where the evidence on accuracy is mixed, the guides say so instead of rounding it up.
Latest from Arnold
4 total
Free Prediction Market Tools Worth Using in 2026
Free prediction market tools worth using: a Polymarket vs Kalshi price comparison, fee, vig and EV calculators, on-chain data, APIs and a trading journal.
Arnold Vezcasi
Prediction Markets for Beginners: Your First Trade
A beginner's walkthrough to your first prediction market trade: choosing a venue, funding, reading a market, placing an order, and the mistakes to avoid.
Arnold Vezcasi
Prediction Market Glossary: Every Term Explained
Every prediction market term explained plainly: contracts, vig, spread, maker and taker, Brier scores, DCM licences, oracles and more.
Arnold Vezcasi