Brier score
A Brier score grades probability forecasts: the average squared gap between each stated chance and what happened, 1 or 0. Lower is better, and 0 is perfect.
Example
Say 70% for a home win that happens: (0.70 − 1)² = 0.09. Say 70% and it does not happen: (0.70 − 0)² = 0.49.
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Related terms
Closing line value (CLV)Closing line value is how the price you took compares with the last price before the start. Beating the close regularly is the best early sign of a real edge.Regression to the meanRegression to the mean is the tendency of an extreme run to be followed by results closer to average, because part of any extreme run is luck.