Common Cause Failure
Updated 2026-08-10
INTRODUCTION
English translation pending.
CORE DEFINITION
A reliability concept from systems and safety engineering, analyzed through fault trees and common-cause models. The core proposition is that redundancy only reduces risk when the redundant paths are genuinely independent, so components sharing a power supply, batch, design, or environment fail together. The key qualification is that diversity rather than duplication is what protects, since two identical copies of the same design share every weakness.
SCAFFOLDING EFFECT
Reduce cognitive load
- Root sharing: check whether the redundant components share a common source, batch, or design. - Diversity requirement: make backups differ physically, functionally, or in timing. - Fault tree pass: trace what single event would disable several components at once.
Anchor fast decisions
Independence is the assumption that gives redundancy its value, because two independent paths fail together only by coincidence. When both paths depend on the same upstream condition, that condition becomes a single point of failure that removes both protections at once. The system then behaves like a single component while appearing to have two.
MINIMUM ACTION
In progress 0/1Practice this model in one real situation:
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Source support: Explicit
- en.wikipedia.orghttps://en.wikipedia.org/wiki/Common_cause_and_special_cause_(statisticsverified
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