Brier score

A measure of forecast accuracy: the average squared difference between your predicted probability and the actual outcome (1 or 0). Lower is better, 0 is perfect, and 0.25 is what you'd get always guessing 50%.

The Brier score rewards being both accurate and confident in the right direction. It's the standard single-number scorecard for a forecaster, and our prediction journal computes it from your graded calls so you can track improvement over time.