The gap between the price you bet and the price the market closed at — the fastest honest read on whether a process is finding something real.
TODO — write this one yourself.
TODO — cover why the close is the sharpest number a market produces, why CLV reads true on a small sample where win rate does not, and how limits at soft books distort the measurement.
Math, not advice. 21+ where legal. If gambling stops being entertainment, call 1-800-GAMBLER.