How Complex Systems Fail

Richard Cook's essay "How Complex Systems Fail" argues that complex systems such as transportation, healthcare and power generation are inherently hazardous, and that catastrophe usually requires several small, individually insufficient failures to combine. The text states that defenses against failure are layered and generally successful, and that complex systems always run in a degraded mode with latent flaws. It also argues that "root cause" attribution after accidents is fundamentally wrong, and that hindsight bias distorts post-accident assessments of human performance.