1/5 Thread: 18 Traits of a complex system
1. Complex systems are intrinsically hazardous systems
2. Complex systems are heavily and successfully defended against failure
3. Catastrophe requires multiple failures – single point failures are not enough
1. Complex systems are intrinsically hazardous systems
2. Complex systems are heavily and successfully defended against failure
3. Catastrophe requires multiple failures – single point failures are not enough
2/5
4. Complex systems contain changing mixtures of failures latent within them
5. Complex systems run in degraded mode
6. Catastrophe is always just around the corner
7. Post-accident attribution accident to a ‘root cause’ is fundamentally wrong
4. Complex systems contain changing mixtures of failures latent within them
5. Complex systems run in degraded mode
6. Catastrophe is always just around the corner
7. Post-accident attribution accident to a ‘root cause’ is fundamentally wrong
3/5
8. Hindsight biases post-accident assessments of human performance
9. Human operators have dual roles: as producers & as defenders against failure
10. All practitioner actions are gambles
11. Actions at the sharp end resolve all ambiguity
8. Hindsight biases post-accident assessments of human performance
9. Human operators have dual roles: as producers & as defenders against failure
10. All practitioner actions are gambles
11. Actions at the sharp end resolve all ambiguity
4/5
12. Human practitioners are the adaptable element of complex systems
13. Human expertise in complex systems is constantly changing
14. Change introduces new forms of failure
15. Views of ‘cause’ limit the effectiveness of defenses against future events
12. Human practitioners are the adaptable element of complex systems
13. Human expertise in complex systems is constantly changing
14. Change introduces new forms of failure
15. Views of ‘cause’ limit the effectiveness of defenses against future events
5/5
16. Safety is a characteristic of systems and not of their components
17. People continuously create safety
18. Failure free operations require experience with failure
Link to this *only* 4-page paper: web.mit.edu/2.75/resources…
16. Safety is a characteristic of systems and not of their components
17. People continuously create safety
18. Failure free operations require experience with failure
Link to this *only* 4-page paper: web.mit.edu/2.75/resources…
