Six Sigma's "Body of Knowledge" (BoK) is the course padding used to justify outrageous prices for worthless belts. It is a pathetic attempt to substantiate the Six Sigma Scam with marketing hype.
The BoK starts with the fundamentals of the Scam, while omitting the embarrassing bits, such as Mr Smith's out-of-control molding process and his buddy Harry's stack of discs. Harry's ludicrous discs formed the "pillar" of his farce. It formed the Scam's laughable 3.4 dpm "metric" that companies like Ford were promised but instead yielded a woeful 220,000 dpm.
COST of QUALITY
Next in the Bok comes Cost of Quality. It ignores statisticians: Dr Taguchi, Professor Deming and Dr Wheeler, who showed that best Quality is achieved when costs are minimized. Focusing on Quality minimizes costs while focusing on cost reduction destroys Quality.
Quality means "on target with minimum variance", not Six Sigma's 1870's go/no-go approach of counting defects.
TQM
Throw in some TQM tools. Harry claimed his Scam was "80% TQM".
CONTROL CHARTS
While the self-confessed con man Harry didn't mention them, control charts are tossed in ... and corrupted. Control charts do NOT depend on the Central Limit Theorem. NEVER normalize data.
Dr Wheeler has proven CuSum and EWMA worthless.
P, U, NP, C charts should NOT be used because they assume a probability distribution. Use XmR charts.
DMAIC
Described by Harry's workmate Bhote as "Muddled, Imprecise, Impotent, Incapacitated, Rudderless", it makes good fodder for the BoK. Dr Wheeler says: "Any claimed DMAIC success is a commentary on how completely disorganized everyone was to begin with."
ENUMERATIVE TOOLS
The rest of the BoK comprises general statistics 101 for ignorant amateurs. Professor Deming warned: "American management have resorted to crash courses in statistical methods, employing hacks for teachers. The result is that hundreds of people are learning what is wrong." He called such general statistics "enumerative methods".
Professor Deming added that enumerative tools "however interesting, are INAPPROPRIATE because they bury the information contained in the ORDER OF PRODUCTION". That is, the SEQUENCE of PRODUCTION DATA IS IGNORED.
"The student should AVOID tests of significance as such calculations have NO APPLICATION in science and industry."
Dr Wheeler adds weight to Professor Deming's statements. "Without making this distinction [of enumerative vs analytic studies], we will inevitably be caught up and confused by the arguments of probability theory and statistical inference to the extent that we will both misapply the techniques and make incorrect decisions." "Unlike all of the various "tests" and "intervals" of statistical inference, Shewhart's charts are tools for Analytic Studies".
Enumerative methods are inappropriate for process improvement.
SUMMARY
BoK is TQM tools plus a mish-mash of junk ... with no philosophy.
by Dr Tony Burns BE (Hon 1) PhD (Chem Eng)