The Truth about Six Sigma Quality ... Fallacies, Faults and Errors



Despite the superlatives and extraordinary claims of consultants, Six Sigma quality contains a host of statistical, logical and common sense errors and fallacies. Read the following articles before embarking on any six sigma project.
A failed program may be as great a disaster for you personally as for your company.

  1. "Sick Sigma." Dr A. D. Burns, Quality Digest, April 2006.
  2. "Tail Wagging It’s Dog." Dr A. D. Burns, Quality Digest, May 2006
  3. "The Six Sigma Zone." Dr Donald Wheeler
  4. "The Confusion Over Six-Sigma Quality", Pandu Tadikamalla, Quality Progress. Milwaukee: Nov 1994. Vol. 27, Iss. 11
  5. "Notes on The Six Sigma Concept" William Latzko
  6. "The Mist of Six Sigma" Alan Ramias
  7. "Freedom from Command and Control" John Seddon, 2005
  8. "Lean Six Sigma - An Oxymoron?" Mike Micklewright, 2006
  9. "The Tactic of Six Sigma" John Dowd, 2006
  10. "Six Sigma Stigma" Martin Kihn, Fast Company, September 2005
  11. "Deming Management Philosophy and So-Called Six Sigma Quality" David Wayne, Motorola, 2006
  12. "Six Sigma: Lessons from Deming" Dr A. D. Burns. July 2007

The Myth of Six Sigma's +/- 1.5 Sigma Drifting Process Average



The Six Sigma methodology is based on 3.4 Defects Per Million Opportunities. "3.4" is used because Six Sigma assumes that process averages drift over time by +/- 1.5 sigma. The graph on the left illustrates this behaviour.

It can be see that this typical six sigma process is wildly out of control. Out of control points are shown in red. Out of control processes are unpredictable and may produce defects, no matter where specification levels have been set.

The "drift" was modified in 2003 to become a "correction" but is equal in nonsense value.