About & Methodology

Every figure carries a confidence tier

The tier drives the figure's colour on the page, and older figures fade toward grey on top of it. Nothing is presented as more certain than its source warrants.

• primary — Primary source, current (≤~3 months). Solid.
• modelled — Our own transparent calculation from primary inputs (e.g. EIA stocks ÷ demand).
• official lagged — Official source, but older than ~1 year.
• estimate — Third-party estimate or inference — shown as a range with a caveat.
• stale — Real once, now old enough to distrust; extrapolated.
• undisclosed — Not publicly available. A known unknown, shown as such — we never invent a number.

We never rank figures that aren't comparable

Days-of-cover can mean very different things — per-product days of consumption (NZ), IEA total-oil net-import cover (Japan, Korea), or commercial stock ÷ product supplied (US). These share no denominator, so a machine-checked comparability rule keeps them in separate facets: you can rank within a facet, never across one. A single bar chart will never imply NZ's 60-day per-product cover beats Korea's 208-day net-import cover — because the two don't measure the same thing.

Where the numbers come from

The daily nowcast, and when we refuse it

Between official releases, the last MBIE figure is rolled forward using recent demand, with the anchor's age folded into an uncertainty band. If the last official figure is more than 45 days old, we refuse to state a current number at all — the tile says "no current estimate," shows the last official value with its age, and draws no forecast. Days-of-cover is never shown below zero.

Help us falsify it

Axiom is built on falsification. Spot a stale number, a better source, or a mistake? The "Challenge / add evidence" panel on the public brief logs corrections for a human to review. Crowd input is never auto-written into the ledger — it's a proposal a person checks against a primary source.