Append-only score history
Append-only means the score database only ever gains rows. When a company is re-scored, the new reading is written next to the old one, never over it. When something needs correcting, the correction is itself a new row. Nothing is edited, nothing is deleted, nothing is backfilled.
Why be strict about this? Because a history you can quietly rewrite isn’t a history — it’s marketing. A track record only means something if it was demonstrably written down at the time, mistakes included. Each row carries the timestamp it was captured and the methodology version that produced it, so anyone can see exactly what the Index said, and when, and under which rules.
How the Moat Index applies this
Company pages render their score history straight from this record, and Moat Movers compares readings to find genuine changes in scored quality. One rule keeps that comparison honest: only rows produced by the same methodology version are ever compared. When the scoring rules themselves change, a company’s number can move without anything about the business changing — so a cross-version move is treated as a methodology transition, never presented as a company upgrade or downgrade. The record grows with the nightly ingest and can’t be recreated later, which is precisely what makes it worth keeping. See the methodology for how each reading is computed.