Bill Smith did not really "invent" Six Sigma in the 1980s; rather, he applied
methodologies that had been available since the 1920s developed by luminaries
like Shewhart, Deming, Juran, Ishikawa, Ohno, Shingo, Taguchi and Shainin. All
tools used in Six Sigma programs are actually a subset of the Quality
Engineering discipline and can be considered a part of the ASQ Certified Quality
Engineer body of knowledge. The goal of Six Sigma, then, is to use the old tools
in concert, for a greater effect than a sum-of-parts approach.
The use of "Black Belts" as itinerant change agents is controversial as it
has created a cottage industry of training and certification. This relieves
management of accountability for change; pre-Six Sigma implementations,
exemplified by the Toyota Production System and Japan's industrial ascension,
simply used the technical talent at handóDesign, Manufacturing and Quality
Engineers, Toolmakers, Maintenance and Production workersóto optimize the
The expansion of the various "Belts" to include "Green Belt", "Master Black
Belt" and "Gold Belt" is commonly seen as a parallel to the various "Belt
Factories" that exist in martial arts.