What it means for a number to be measured
How can you tell a counted number from a guessed one?
Every betting tool shows you numbers. Almost none of them tell you which ones came from data and which came from somebody's assumption typed into a constant. The difference decides what a number is worth, and it is invisible unless the tool says so on purpose.
Three kinds of number
Arithmetic. Break-even on a pair of prices. A parlay's payout. These cannot be wrong, only misread — the totals middle above breaks even at 4.76% and no data would change it.
Measured. Counted from a record: how often a window hits, what a book's margin actually is, how much your simultaneous bets co-move. Worth what the sample behind it is worth, which is why the sample size belongs on screen next to it.
Prior. A stated constant standing in until there is something to measure. Legitimate, necessary, and dangerous the moment it stops announcing itself.
The bars, and why they exist
| Claim | Needs |
|---|---|
| Counted margin window | 200 recorded games |
| Counted totals window | 400 games, and 8 per distinct total |
| Measured correlation | 30 settled bets, 20 multi-bet groups |
| Fitted model weights | 30 graded bets, 30% held back in time order |
| Per-book weights | 20 graded bets at that book |
Under any of these, the number does not become uncertain — it becomes a prior, and it says so. An unmeasured cell is not a zero, and a stale quote is not a fresh one.
The test
Ask any tool where a number came from. If it cannot answer, it is not that the number is wrong; it is that nobody can tell you whether it is. Every figure on this site is computed by running the engine at build time, and the build refuses to publish a figure that is not.