Define the benchmark first
Closing can mean the last available price at one operator, a market average or a sharp reference source. Choose one definition before collecting data.
The same market, line, settlement rules and odds format must be used. Otherwise the comparison mixes different propositions.
Price CLV and line CLV
For a fixed line, compare the implied probability or decimal price captured earlier with the closing price. For spreads and totals, both the number and attached price matter.
A better line can be more important than a small attached-price difference, especially around commonly occurring margins.
Sample size and selection bias
A short sample can show positive CLV by chance. Selectively recording only favorable movements makes the metric meaningless.
Log every qualifying observation using the same timestamp rules, including cases where the price moves against the original view.
CLV is a diagnostic, not income
A person can beat a chosen closing benchmark and still lose money over a period. Margin, variance and benchmark quality all matter.
Never use CLV claims to promise returns or encourage higher risk. It is one audit measure within a broader responsible process.