Closing Line Value (CLV) is the difference between the odds you bet and the closing line — the odds just before the game starts. It's widely regarded as the best real-time proxy for whether a bettor has genuine edge.
The closing line aggregates all available information: sharp money, late public action, injury reports, and weather. If you consistently bet at better odds than the line closes at, you're demonstrating that you identified value before the market caught up. That's the definition of a sharp bettor.
CLV matters more than win rate. A bettor with 52% win rate and consistent negative CLV is likely running hot. A bettor with 48% win rate and consistent positive CLV is likely running cold on a good process.
Tracking CLV requires logging the odds at bet time and then recording closing odds for every wager. The formula: CLV % = (Closing Implied Probability − Bet Implied Probability) / Bet Implied Probability × 100.
Positive CLV doesn't guarantee short-term profits, but across large sample sizes it's the strongest signal your model or handicapping process is generating real alpha.