How accurate were the odds?

If markets priced at 70% happen about 70% of the time, the prices are well calibrated. We take each market's price 7 days before it closed and compare it with the outcome.

Calibration

The accuracy record could not be read right now.

How it is measured

Every hour we note the price of each open market that closes in 6 to 8 days. When the market settles Yes or No, that price and the outcome become one record. Markets we did not see 7 days out are not counted, so nothing is estimated after the fact.

The Brier score is the average of (price − outcome)², with the outcome as 1 or 0. Always answering 50% scores 0.25; lower is better.

Markets that settle at a price other than Yes or No are left out.