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.
17 of 17 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 64.9 before per-incident rounding. Averaging every scored incident's own (rounded) severity gives 65.1 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 | 18.0 | 25.0 | 72% |
| Scale/breadth of those affected | 15 | 5.1 | 15.0 | 34% |
| Irreversibility | 20 | 11.5 | 20.0 | 57% |
| Autonomy of the failure | 20 | 11.8 | 20.0 | 59% |
| Precedent/systemic weight | 20 | 18.5 | 20.0 | 93% |
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 |
| 1972 | 4.0 | 2.0 | 3.0 | 2.0 | 4.0 |
| 1979 | 4.0 | 1.5 | 3.5 | 2.0 | 4.0 |
| 1981 | 4.0 | 1.0 | 3.0 | 2.0 | 4.0 |
| 1985 | 2.0 | 1.0 | 1.0 | 2.0 | 3.0 |
| 1992 | 4.0 | 1.0 | 3.0 | 2.0 | 4.0 |
| 1993 | 4.0 | 1.0 | 3.0 | 2.0 | 3.0 |
| 1994 | 4.0 | 2.0 | 3.0 | 2.0 | 4.0 |
| 1995 | 4.0 | 1.0 | 3.0 | 2.0 | 4.0 |
| 1996 | 4.0 | 2.0 | 3.0 | 2.0 | 3.0 |
| 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 |