Human error is a reality of people being involved in operations and attempting to prevent human error from occurring would be like trying to hold the tide back with your bare hands — it simply will not work.  Instead, review and design a system that protects the oerational assets (including the person) from any harm that could occur when the error does present itself.  This is a much smarter approach to risk management and risk mitigation than trying to prevent all the errors from occuring in the first place.

There is no person that walks upon the face of the earth that is not susceptiable to committing an error.  The human person is not an error free mechanism.  Depending upon which studies and reports you read you will find that the error rates committed by human beings range from 1 to 15 errors per hour.  For example, the Civil Aviation Safety Authority of Australia suggest that people make roghly 50 errors per day (3 - 4 per hour).  And Dr. Trevor Kletz in his book, An Engineer’s View of Human Performance, suggests that people are 99.7% reliable (3X10-3); or that they will experience 3-4 errors in 1000 attempts when engaged in a deliberate activity.

The better management approach from a systems perspctive is to fully grasp the reality that people will commit errors and thereforer work to prevent the consequences from those errors from causing significant problems.  This is not to say that one should abandon the training, development, coaching and drilling of people to be be better, but simply to say that training alone will not prevent human error from occuring and therefore all your risk mitigation eggs should not be solely in that basket.  Instead build systems that can absorb those errors when they occur that do not injure the person or cause unnnecessary harm to the assets in question.  That is the better and wiser management approach.