Institutional
Methodology
How figures are produced, labelled and revised. Every index carries its own method document, version and weight table; this page states the rules that apply across all of them.
Provenance is recorded before publication
No figure is published without a provenance label, a source, a date and, where the figure is modelled or forecast, a method version and a confidence value. A value that cannot carry those fields is not rendered.
The five labels are observed, reported, partner data, modelled and forecast. Their definitions are set out on this site and are not varied between pages.
Coverage gating
Each index states a minimum input coverage ratio. An entity below that threshold is listed as unassessed. It is not scored with a caveat, and it is not interpolated from neighbouring entities.
Weights are fixed before computation
Index weights are published before an edition is computed. A change to a weight requires a published rationale, a new method version, and recomputation of the historical series so that comparisons remain valid.
Every weight has a written justification in the method document for its index. A weight does not exist because it produced a preferable ranking.
Sensitivity is tested and reported
Before an index edition is released, the weighting is randomly perturbed across a large number of trials and the mean movement in rank is recorded. Where a ranking is unstable under reasonable reweighting, either the index is redesigned or the instability is published alongside it.
Editions are immutable
A published index edition pins a method version and an input snapshot and can be recomputed exactly. Corrections produce a new version with a documented delta rather than a silent amendment.