The benchmark, snapshot by snapshot.
The benchmark refreshes quarterly, and every refresh ships as a snapshot. This page is the changelog: one entry per snapshot, nothing invented in between.
What a snapshot is. A frozen, immutable copy of the catalog — every item, every observation, every band — derived at one moment and never edited after publication. New data lands as the next snapshot, never as a silent change to this one.
Why it matters. Every page on this site stamps the snapshot it was rendered from (check the footer). A band you cite today is reproducible: the same snapshot shows the same band, for as long as it exists.
The benchmarked figure above is computed from the live snapshot the same way the catalog index computes it, not quoted from marketing copy. How an item earns a published range — the three-vendor gate, independence checks, confidence tiers — is documented on the how-it-works page.
This is the first public snapshot, so this entry is a baseline rather than a diff. From the next refresh on, each entry lists what actually moved: items added, bands that formed, bands that shifted.