Rankings ledger
Rank history
Where any ranked product stood on any day since the rankings ledger began, and its rank over time. Every value is read back from the public ledger, and each build refuses to publish these files unless every day's order equals the ledger's own replay.
The raw record, with each line chained to the one before it, is the rankings ledger; the failures it is read against are on the calibration page.
Pick a category to read its whole order at the end of any day, with the methodology version in force that day. Pick a product to read its rank on that day, how long it has held it, and its rank over time as a step chart with #1 at the top; the table under the chart lists every change the ledger recorded with its cause, such as a row that crossed it or a new methodology version. A day before the ledger began shows its first recorded order, and a product that was not ranked yet is said to be unranked, never given an estimated rank.
Reading the rank history…