Claims, Not Facts: Building an Auditable Multi-Author Record for a House

Most systems that store information about a building consider the data as true facts once it is entered. However, this approach is problematic when multiple parties are updating the same information. At ML Systems, they developed a system called the Master Ledger that stores claims instead of facts. The ledger records the source, evidence grade, and verification state of each claim, without automatically selecting a winner.

This system allows for multiple parties to describe the same house simultaneously, each with their own expertise. The ledger reconciles claims based on authority and evidence, rather than blindly accepting the first input. For example, while a homeowner might incorrectly state the number of stories in a house, the assessor would be authoritative on the number of stories.

The evidence ordering is two-dimensional, first by domain ownership, then by evidence grade. Conflicts between credible sources are kept in the record, with the understanding that this information is still important to the house. Independent verification of claims is done through multiverification, where each party signs off on the claim.

A claim's status is determined by the number of independent verifications, not by the highest-ranked signature. This ensures that the record remains auditable and transparent, with no hidden audit trails. The Custodian's oversight console presents a review queue based on priority, rather than submission events, ensuring that all claims are eventually reviewed.

The ledger is presented in a record-first UI, with visible rating and verification glyphs to indicate the current status of each claim.