What closing line value is
Closing line value is the gap between the price you took and the price the market settled on at kick-off. Take 2.20 on something that closes at 2.00 and you are 10% ahead of the closing line. Take 2.00 on something that closes at 2.20 and you are 9% behind it.
The closing price matters because it is the market's last and best answer. It has absorbed the team news, the money and the weather. Individual bookmakers are beatable; the closing price of a sharp book sits close to the true probability, minus a small margin.
Why results lag
A 55% strike rate over 40 bets tells you almost nothing, because the plausible outcomes for a real 5% edge and a real 0% edge overlap heavily at that sample size. Closing line value converges faster, because every bet contributes a measurement rather than a coin flip.
| After | Profit tells you | CLV tells you |
|---|---|---|
| 50 bets | Nothing | A direction |
| 250 bets | A direction | Fairly clearly |
| 1,000 bets | Fairly clearly | With confidence |
How to record it
Log the price you took and the time you took it, then capture the closing price when the event starts. Reko does the second part for you when closing odds capture is on, which matters because guessing a closing price after the fact is worse than not recording one.
Express it as a percentage rather than in points, so a 1.50 shot and a 12.00 shot are comparable. Your price divided by the closing price, minus one.
What a good number looks like
Consistently positive is the bar, not spectacular. Recreational bettors run at minus 4% to minus 8% against the close. Break even is roughly zero after the margin. A steady plus 2% to plus 3% across a real sample is a genuine edge, and at sane stakes a profitable one.
One warning: closing line value can be gamed by betting into stale prices at soft books that never move. If your CLV is strong but the profit never follows, check whether the books you beat are the ones setting the closing price you measure against.