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 Editor
Arnold Vezcasi
Writes PredictReport's explainers and reference guides: beginner walkthroughs, the glossary, research on how accurate markets are, and the tools traders use.
4 articles
About Arnold
Arnold Vezcasi writes the explainers and reference guides that sit underneath the rest of PredictReport: the walkthrough for a first trade, the glossary of the terms traders use, the research on how accurate prediction markets actually are, and roundups of the tools worth using.
The aim of the beat is practical. Someone arriving with no background should leave able to read a market, understand what a price means and what a trade costs, and make an informed decision about whether to take part at all.
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