Some Notes on Six Sigma (2000/04)

HanChing Chung

Some people like the powerful advertised commercial package of so-called Six Sigma programs. Some advocates are like the following,

"Six Sigma is not the statistical concept of .002 ppm vs. 3.4 ppm, nor is it a methodology in and of itself. It is a synthesis of Juran's 'Project by Project' improvement, Kaizen, and solid industrial engineering methods brought together with the System of Profound Knowledge at it's core. It depends on measurable attained to keep it alive in the eyes of the top level management, to keep it interesting to the people affected by it, and to sustain the 'priestly caste' of the black belt."

If you try to understand Six Sigma by traditional statistical terms, you will probably go down the road that I originally traveled. Although it is based on that statistical concept, it is NOT the same thing. Striving for six sigma quality means that you are striving for an aggregate equivalent to six sigma.

I throw some stones or ices on them as follows,

Well, one more time, people are dreaming or advertising for a grand and amazing super-string and 'end of the history' and putting it all together sect or committees? Or is this like one more of the emperor's new clothes?

It might be good idea not to put SoPK into 'guilty by association' which Dr Deming thought most 'packaged deals and labels like TQM misled his teachings.

Several good papers by some respected statisticians in American Statisticians and Quality Progress during 1999 are available now. But I think this time might be final calls for this strong commercial 'movement'. In the market, several expensive books are available for us to review, so let's talk about specific points.

If we talk about the origin of Six Sigma thinking, I think the best books might be by some Japanese authors written about 20 years ago. They are for 'process capability studies', 'TQC' and 'Parts per billions (PPB) program'.

The complexity of products and industrial supplying chains made this kind of demand high yield and reliability of parts of a system. The manufacture or the service processes demand nearly zero defective or high processes capabilities.

But as Dr Deming points out in Out of the Crisis that the continual improvement demands leadership, teamwork and knowledge, not by slogans or work standards setting like Six Sigma.

One possible explanations of the re-emergence of Six Sigma is like the Work Simplification or SPC programs nearly 50 years ago. After the '80 'quality movements and the booming of programs like ISO, various Prizes, Schools of Guru X and YZ Movements, a professional and an industry is maturing, so thee so-called 'synthesis' will be continued and so for the grand slogan search...These are facts of life.