What it is for
- Finding events that touch infrastructure or institutions the wider system depends on — a grid, a strait, a clearing house, a sole-source supplier.
- Triaging a large result set down to the few events with structural consequences, rather than the loudest ones.
- Screening for single points of failure in a supply chain or a market you are exposed to.
- Pairing with
propagation_potential— a dependent node plus a live transmission channel is the shape of a spreading disruption.
Filter on it
systemic_importance_min and systemic_importance_max on GET /api/v2/events, range 0–1. Published only for the cameoplus family — filtering on it excludes every event outside that family.
Formula
Every sub-factor is clamped to its stated range before it enters the equation, and the result is rounded to 2 decimal places. Reproducing a served value needs both.
What the coder scores
The coder reads these off the article and records a reason for each. The scaler above turns them into the value — nothing else feeds it.size
How big/central the node is (0-1).
interconnectedness
How many others depend on it (0-1).
irreplaceability
How hard it is to substitute; 1 = a unique chokepoint (0-1).
The frameworks it adapts
BCBS G-SIB assessment methodology
What we take from it. The size / interconnectedness / substitutability triad and the EQUAL weighting of indicator categories — not the balance-sheet inputs, which we do not have. In current use by the FSB, which publishes the G-SIB list annually from it — 29 banks in the 2025 list, setting capital buffers effective 1 January 2027.The full citation trail
The BCBS G-SIB / FSB SIFI assessment methodology and the ECB/EBA O-SII framework, extended with CISA critical-infrastructure sectors and network centrality (Freeman, 1977). The size / substitutability / interconnectedness triad comes from the IMF-BIS-FSB 2009 G-20 guidance, not from BCBS directly. We ADAPT the structure and vocabulary of these frameworks. None of the bodies named endorses, reviews, or is connected to this metric, and their use does not make our values empirical measurements.Worked examples
Real events from the corpus, scored by the coder and frozen here on 2026-08-19 — check the arithmetic against the formula above. They are snapshots, not live lookups: an event can be re-coded, and an example that changed underneath its own arithmetic would be worse than none.Vessel owners reduce Strait of Hormuz traffic amid standoff
Iran · 2026-08-11 What a near-maximum looks like. The node is named first — the Strait itself — and all three properties are then scored about that, not about the news.systemic_importance = 0.92 — what GET /api/v2/events returns for this event.
Britain seizes Russian tanker Smyrtos in English Channel
United Kingdom · 2026-08-13 A dramatic event on a modest node. Royal Marines boarding a tanker scores 0.32, because the metric asks what the system depends on — not how striking the event is.systemic_importance = 0.32 — what GET /api/v2/events returns for this event.
When it is NULL
Never null with a value attached — a stated 0 means “the node is not systemically important”, which is a judgement rather than a missing reading. Instead the metric is ABSENT from the response entirely, in two cases: a conflict-family event (the four CAMEO+ metrics are omitted rather than returned as 0, because a 0 would assert “measured, and it is the minimum”), and an event coded before the v2-2026-07-24 contract. Absence is the only representation of UNKNOWN here; a served 0 is an assertion.
What this number does not claim
What this number does not claim
These are the readings the definition does not support — building on one of them is building on a promise nobody made.
- NOT a Basel score, and NOT endorsed by anyone. We ADAPT the shape of the G-SIB / O-SII regimes; those regimes score INSTITUTIONS on balance-sheet data we do not have, and we score the NODE AN EVENT TOUCHED on rubric anchors instead. None of BCBS, the FSB, the ECB/EBA or CISA endorses, reviews, or is connected to this metric.
- NOT a measure of the event’s severity, reach, or newsworthiness. It scores the node’s standing in the system, which is why a routine measure should score near 0 rather than promoting the country itself into a node.
- An ordinal ranking signal, NOT a quantity. Good for sorting and triage; not for asserting one event is 1.4× another.