Poka yoke

People are human and cannot be expected to do everthing like a machine, exactly the same each time. A simple distraction can lead to a part of their work being done wrong. It is also not necessarily their fault, as poorly-designed processes that require a great deal of attention can contribute severely to problems.

Poka yoke is a Japanese term which simply means mistake-proofing or fool-proofing and implies designing work and processes such that it is impossible or very difficult to for people to make mistakes. It is a simple principle that can lead to massive savings.

Thus, for example, a plate that must be screwed down in one orientation only could have the screw holes in non-symmetrical positions so that it can only be screwed in the right orientation.  The principle can be easily used in non-manual situations (where mistakes can have huge costs associated), for example in a project management process, checklists may be used at various times in the project to check that particular tasks have not been forgotten. 

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