Win/loss is noisy. In a small sample, a brilliant bettor can lose and a fool can win. So how do pros measure their skill?
Closing Line Value (CLV). Did you get a better line than the market settled on by game time?
If you bet Pistons -3 at -110 and the line CLOSES at -4 (-110), you got value. The market moved toward your side after you bet. You "beat the closing line."
Pinnacle Sports analyzed thousands of bets and found that closing odds at sharp books correlate with true outcomes at R² = 0.997. Translation: by game time, sportsbook lines are nearly perfect predictors of true probability.
If you beat that line — get better odds than it closes at — your bets, in aggregate, must have been priced too low when you took them. Over hundreds of bets, this is the most reliable signal of skill.
Win rate lags. After 20 bets, win rate is dominated by variance. CLV reveals skill faster.
Log your bet odds + closing odds for every bet. Compute CLV. Average over 50+ bets. If average CLV > 0, you have an edge.
Lines move toward truth as game time approaches. If you have a real edge, betting early often gets you the better line.