What is closing line value

Why do sharp bettors care more about CLV than profit?

Closing line value is the difference between the price you took and the price the market settled at. Beating the close consistently is the standard evidence that an edge is real.

The reason it matters more than profit is sample size. A 2% edge over 500 even-money bets has a standard deviation of about 4.5% of turnover, so losing months are routine and winning months prove nothing. Here is a real 220-bet record:

+5.91% flat-bet ROI, but the interval spans zero (-7.0% to +18.9%) — indistinguishable from break-even

That is +1,300 in profit and it still cannot be distinguished from break-even. Waiting for profit to confirm a model means waiting years; adjusting on early profit means fitting noise. CLV converges far faster, which is why it is what this engine calibrates on rather than merely displays.

One catch: grade against the devigged closing price, not the raw one. Comparing two vigged prices understates your edge by the closing margin. The arithmetic →