Kelly Criterion

A staking formula that sizes each bet in proportion to its edge and the odds, maximizing long-run bankroll growth. Many bettors use a fraction (e.g. half-Kelly) to reduce variance.

• Edge — The model's estimated advantage over the market — the gap between its projected win probability and the probability implied by the price.
• Unit — A standardized stake (typically 1–2% of bankroll) used to track results independent of dollar amounts, e.g. +12.5u.