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Team Performance Module navigation.
Module Introduction
Lesson Goals
Team Use
Decision Making
Team Types
Development
Goals
Motivation
Performance
CRM
Human Error
CRM Model
Systemic Model
Error Management
CRM Effectiveness
Module Summary
Course Conclusion
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Team Performance Module > Human Error - 3 of 6
 
 


Human Error - Systemic Model

Defects in systems design, training, maintenance or the organization can lead to human error. These defects can lie dormant for lengthy periods of time until a combination of latent conditions and active human error trigger an accident. Accidents are seldom the result of a single event; most result from a series of events in an "error chain."

James Reason's Human Error Model is termed the "Swiss Cheese" Error Model. In the illustration below the slices of cheese represent defenses built into safety critical systems to "deflect/stop" error. However, in reality, no system or human within-the-system is perfect. Imagine the slices of cheese rotating like disks around a horizontal axis. Further imagine that the "holes" in the defenses are not only repositioned due to disk/slice rotation, but are also constantly moving around on each piece of cheese and are opening and closing. When the holes in the defenses line-up, the error (arrow) can penetrate the defenses and an accident occurs.*
The slices of cheese represent defenses against accidents and incidents. The holes in the cheese are holes in these defenses. Some holes are due to human errors/mistakes while other are caused by latent conditions. (adapted from Reason, 2000)

* Reason, J, "Human Error: models and management," BMJ 2000: 320: 768-770.

  
 

   

  
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