Closing line
also: closing spread · close · final line
The last price a market offered before kickoff, and the most accurate public forecast of a game that exists.
A line opens on a book's own number and then moves with the money. By kickoff it has absorbed injury news, weather, lineup changes and every opinion anyone was willing to back, which is why the closing line beats almost every public model at predicting outcomes.
That makes it the benchmark rather than the target. A model that agrees with the close has learned the market; one that disagrees is making a claim, and the only way to know whether the claim is worth anything is to record where the line closed and check later.
Both the opening and closing snapshots are stored per book, so the distance a line travelled is recoverable rather than inferred. That distance is usually more informative than the final number.
Comparing a model's picks against the opening line because that is what was available when the pick was made. Grade against the close, or you are measuring how fast you were rather than how right.
Where to get it
Related
Closing line from the API
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