Term
Edge
Your modelled probability advantage versus the sportsbook’s implied probability.
Definition
In sports betting, edge is the percentage gap between your assessed probability of an outcome and the implied probability baked into the sportsbook's odds (after removing the vig). A positive edge means the bet is +EV; a negative edge means you are paying the bookmaker more than the bet is worth. It is the foundation of every other skill metric.
Example
Decimal odds of 2.10 imply roughly 47.6% (1/2.10). If your model says the true probability is 52%, your edge is 52% − 47.6% = +4.4%. Sized correctly (see Kelly), bets at +4.4% edge grow a bankroll long-term.
Why it matters
Edge drives both ROI and CLV. Without a quantified edge you are guessing; with one, every Bettor Score component compounds in your favour over a sufficient sample.
Related terms
Expected ValueEV
A probability-weighted average return — the long-run profit or loss per unit staked if the same bet were placed indefinitely.
Kelly Criterion
A formula that prescribes the bet size which maximises logarithmic bankroll growth given a quantified edge and odds.
Closing Line ValueCLV
The difference between the odds you locked when placing a bet and the market closing odds — positive CLV signals a real edge.
Bettor Score
A 0–100 composite metric measuring betting skill across five weighted components — ROI, CLV, volume, variance control, and edge factor.
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