Closing Line Value (CLV): Comparing Entry and Closing Prices
Closing Line Value compares an entry price with a specified closing benchmark for the same selection and market. Define the source, timing, and calculation before recording it. CLV is a useful process signal, not proof of expected value, forecast correctness, or profitability.
Define the Comparison First
Record the operator, selection, market, handicap or total, settlement rules, and timestamp for both entry and close. In this guide, the close is the last available quote from a chosen source before the scheduled start. Do not change the source after seeing which comparison looks best.
This guide uses raw implied-probability CLV: closing q minus entry q, reported in percentage points. A positive result means the entry paid more than that closing quote for the same winning outcome. It is not a dollar profit or a standardized measure shared by every analyst.
If the entry spread is -3 and the closing spread is -4, the selection condition changed. Record that as line movement separately rather than treating the two raw probabilities as prices on an identical outcome. Changes in overround can also affect raw-price CLV.
Equal Records, Different Realized Profits
Hypothetical realized sample: each forecaster makes 100 win/loss bets at $100 each, wins 55, and loses 45. Every bet for Alice is priced -108; every bet for Bob is priced -125. These are constant prices, not arithmetic averages of changing odds. Ignore fees and taxes, and round only the displayed final result.
| Forecaster | Price on every bet | Total net profit on $10,000 staked | Average net profit per $100 bet |
|---|---|---|---|
| Alice | -108 | +$592.59 | +$5.93 |
| Bob | -125 | -$100.00 | -$1.00 |
Alice: 55 × ($100 × 100/108) - 45 × $100 = +$592.59. Bob: 55 × ($100 × 100/125) - 45 × $100 = -$100.00. Divide each total by 100 bets for the per-bet averages.
This example isolates realized payout differences while holding the observed record constant. No closing prices are given, so it cannot establish Alice’s or Bob’s CLV. Nor does a realized 55% win rate establish a 55% true win probability.
Worked Entry-to-Close Comparison
Assume the same outcome and rules throughout: entry +150, selected closing quote +130. Entry q = 100/250 = 40.00%. Closing q = 100/230 ≈ 43.48%. Raw-price CLV = 43.48% - 40.00% ≈ +3.48 percentage points.
An opener is a third observation. If an outcome opens +150, you enter +140, and it closes +120, the entry is worse than the opener but better than the close. Opening-to-entry movement and entry-to-close CLV answer different questions.
The conversion formulas and their limits are shown in the odds-to-probability guide.
Interpret the Benchmark Without Overclaiming
A close is another market quote, not the unknown true probability. Source selection, changed margins, liquidity, timing, and sample selection affect the comparison. Positive CLV does not guarantee positive EV or long-run profit; a favorable move can precede a loss.
Report the sample size, missing closing observations, mean, and distribution. Keep different sports and market types identifiable. There is no universal percentage-point threshold in this guide that labels a forecaster profitable or “sharp.”
Seeking the best available price improves the payout for the same outcome. Acting earlier does not guarantee a better closing comparison. Chasing a move can give a worse price than someone who entered before the market moved, but movement alone says nothing conclusive about either entry’s expected value.
OwnTheLines and a Separate Closing Log
OwnTheLines preserves the price attached to a simulation selection. It does not currently provide post-lock closing odds or a cumulative CLV report. Use a consistently chosen external closing source and a separate log if you want to practice this comparison.
For related interpretation, read the logic of line movement and statistical variance.
Frequently Asked Questions
What is closing line value?
CLV compares an entry price with a specified closing benchmark for the same selection, market, line, and settlement rules. This guide reports closing raw implied probability minus entry raw implied probability, in percentage points.
Do better entry odds prove positive CLV?
No. A closing price is required. A comparison of entry odds and realized wins can demonstrate payout differences, but cannot establish either entry's relationship to the close.
Does positive CLV prove profitability?
No. It is a process benchmark. Margin changes, source choice, market conditions, and sampling affect it; a favorable comparison does not establish true probability, positive expected value, or future profit.