Evidence ledger
Also called: sealed claim ledger, prediction track record.
An evidence ledger is a time-locked record of predictions. Every finding a simulation makes is written down and sealed before the campaign runs, then graded HIT or MISS against what actually happened. Because the claim is sealed before the outcome exists, the resulting accuracy rate cannot be reconstructed after the fact, which is the only thing that makes a vendor’s accuracy claim worth anything.
The problem it solves
Any vendor can claim an accuracy number. Almost none can show you the losing predictions. The standard move is to collect outcomes first, then describe which ones the model “would have” called, a claim that is unfalsifiable and therefore worthless to a sceptical CFO.
Sealing fixes this. The prediction is written, timestamped, and locked at the moment the simulation runs, before the campaign is live and before any outcome exists. When the result arrives, the only remaining action is grading. Nothing can be edited, re-scoped, or quietly dropped.
How grading works
- The customer grades, not the vendor. Each sealed claim is marked HIT, MISS, or CAN’T-GRADE by the customer’s team against their own data.
- Misses stay in the denominator. A ledger you can remove entries from is not a ledger.
- Can’t-grade is a real outcome. Some predictions cannot be checked against available evidence, and pretending otherwise inflates the rate.
- Grades feed back. Confirmed findings raise the weight of that pattern for that account; misses lower it. The model gets sharper for that customer specifically.
WhyUser’s current published position: 473 claims graded, 84% accuracy across live accounts, with the method and the known blind spots on the same page.
Why this is the part that compounds
The simulation itself is reproducible. Anyone with a capable model and a few weeks can build a version of it. What is not reproducible is a record of predictions sealed at specific times and graded against real outcomes, because that record can only accumulate at the speed of real campaigns. A competitor starting today cannot buy last year’s sealed claims.
For the buyer, this matters for a plainer reason: it is the artefact you take to your CFO. Not “the tool says the page is broken,” but “here is a record of what it predicted before the campaign ran, and here is how often it was right, graded by us.”
Questions people ask about evidence ledger
What is an evidence ledger?
It is a record of predictions sealed before an outcome exists, then graded HIT or MISS against what actually happened. Sealing before the fact is what makes the resulting accuracy rate verifiable.
Who grades the claims?
The customer, against their own data. A vendor grading its own predictions is not evidence, and misses stay in the denominator.
Why does sealing matter?
Because a prediction described after the outcome is unfalsifiable. Sealing at the moment of the run means the claim cannot be edited, re-scoped, or quietly dropped once the result is known.