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ZD – Zero Defect

Created by Phillip Crosby while working at Martin-Marietta from 1957 to 1965, First controversial debates over the theory started in the 1960’s*, one aspect involves the concept that all self-controlled workers have no reason to make errors, also known as defects. If workers are appropriately motivated, they will actually make no errors, and thus Zero Defects.

Zero Defects was seen by some groups as being unrealistic until Six Sigma concept and 3.4 ppm or almost zero defects was introduced. 

Some companies initiated motivational programs, under the urging of the DOD, (Department Of Defense), but some of these undertakings consisted of little more than motivational propaganda which had little effect on quality.

Some enhanced programs included a suggestion styled scheme for quality improvements. That concept was adopted by Motorola and lead to the six sigma concept of suggestions for saving money in every process and department measured by RONI, (return on net investment) and RONA, (return on net assists) based on worker suggestions.

The fatal error of the hypothesis was …

  • operator errors are the main foundations of defects
  • that all operator errors can be resolved with the proper driving forces.

While winning approval with some managers, there appears to be no basis in fact for this theory. What the facts indicate are that …

  • over 80% of defects are management controlled, not operator controlled
  • the scope of the number of places where an operator could cause an error made the remedies more complex than just motivations.

*Quality Planning & Analysis, 2nd edition, Copyright 1980, Juran/Gryan pg. 138

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Last Updated: Saturday, 10-Jun-06 15:50:57 PDT

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