The simple idea
If Sports Rounders publishes a team at +120 and the same market closes +105, the earlier ticket captured a better return. That is positive closing-line value. If the market closes +135, the published +120 missed a better later price.
How we calculate it
For moneylines and price comparisons, we convert both sides of the same sportsbook market into implied probabilities, remove the bookmaker margin, and compare the selected side’s locked fair probability with its closing fair probability.
The report also shows the relative percentage change because it is easy to compare across prices.
Spreads and totals need two measurements
A move from +3.5 to +3 is not just an odds change—the half-point itself has value. We report line movement separately from price movement and do not collapse them into a misleading single number without a validated conversion.
What CLV cannot prove
One positive close does not prove a model is profitable. CLV becomes useful across a forward, consistently captured sample. It also does not turn a losing ticket into a win; it evaluates the price decision independently from that game’s result.