Index History & Methodology
Every scoring-model version and methodology revision in the published record, with its full description and dates, and the daily index as it was recorded. Historical scores are never restated, filled or interpolated.
Model versions and methodology revisions
In date order. The numbered markers on the homepage trend link to these entries. A model version changes the scoring model and is stamped on every daily snapshot; a methodology revision changes how one dimension is measured inside a model version. Each entry's effective date is the first stored daily snapshot built under it (snapshots are built at 00:00 UTC).
Comparability across versions
A score is comparable with another when both were computed by the same model version and methodology. Across a model version, the homepage trend joins the last observation before the change and the first one after it with a dashed connector: a visual guide, never a value. Across a methodology revision, earlier days keep the score they were published with and are not restated, so the affected dimension may not be directly comparable on either side. The score-history comparisons state a change only where no methodology change affecting that series falls inside the windows compared.
Daily index
Every day from the first stored snapshot, newest first, with the score exactly as recorded.
- Observed — a full daily observation; drawn as the solid line.
- Missing (partial coverage) — a score was recorded, but a dimension was unavailable or a scoring input could not be read; the recorded value is shown and is not comparable.
- Missing — no snapshot was recorded, or it could not be read.
Reading the stored daily snapshots…
Dashed segments connect available observations across periods with missing data. They are visual guides only and do not represent measured values. Interpolated positions are never stored, scored, averaged or summarised. Each date opens that day in the daily change archive. The data is also available from ICHI data exports.