Severity factors
Every incident's 0-100 severity score is decomposed into five weighted factors - harm, scale, irreversibility, autonomy, and precedent - so a reader can see exactly how a number was reached, not just trust it. This page shows which factors actually drive severity across the record, and how that composition has shifted over time.
9 of 9 incidents have a five-factor severity breakdown recorded.
Which factors drive severity
Mean contribution to the final severity score, averaged across every scored incident, shown as a percentage of each factor's own maximum possible contribution so the five bars share a comparable 0-100% scale despite their different weights. Each factor's contribution is its 0-4 rubric score times its weight, divided by 4 - the same arithmetic the site's combination rule uses to compute severity itself.
These five mean contributions sum to 58.9 before per-incident rounding. Averaging every scored incident's own (rounded) severity gives 59.1 instead - the small gap is normal per-incident rounding, not an error: each incident's severity rounds to a whole number before entering that average, while the five contributions above average the exact pre-rounding decomposition.
| Factor | Weight | Mean contribution | Max contribution | % of max |
|---|---|---|---|---|
| Realized harm | 25 | 13.2 | 25.0 | 53% |
| Scale/breadth of those affected | 15 | 4.6 | 15.0 | 31% |
| Irreversibility | 20 | 8.9 | 20.0 | 44% |
| Autonomy of the failure | 20 | 13.3 | 20.0 | 67% |
| Precedent/systemic weight | 20 | 18.9 | 20.0 | 94% |
Factor composition over time
Mean raw factor score (0-4) per year. A month- or year-precision incident is bucketed at the year it happened, never at a finer position than its source actually supports.
| Realized harm | Scale/breadth of those affected | Irreversibility | Autonomy of the failure | Precedent/systemic weight | |
|---|---|---|---|---|---|
| 1966 | 1.0 | 1.0 | 1.0 | 2.0 | 4.0 |
| 1979 | 4.0 | 1.0 | 3.0 | 2.0 | 4.0 |
| 1981 | 4.0 | 1.0 | 3.0 | 2.0 | 4.0 |
| 2016 | 0.5 | 1.0 | 0.5 | 2.5 | 4.0 |
| 2018 | 2.0 | 1.0 | 1.5 | 2.5 | 3.5 |
| 2023 | 3.0 | 1.0 | 2.0 | 4.0 | 3.0 |
| 2026 | 2.0 | 3.0 | 3.0 | 4.0 | 4.0 |