Re: SIX SIGMA

[GrantBlair@aol.com]

In a message dated 3/13/2000 2:44:57 AM Eastern Standard Time, 
gtp@excels.demon.co.uk writes:

<< Can anyone direct me to the "Years of theoretical and empirical research
 on this subject, that have proven this to be true"?
  I really do need some guidance !!
 Regards
 
 -- 
 Terry Peterson >>

According to conventional theory , a process with specifications at +/- 3 
sigma limits will only produce 27 parts per thousand defective in the short 
run when kept exactly on target. In the long run, however, even the most 
closely controlled process will drift from target as much as 1 sigma before 
the shift can be detected and corrected.
Allowance  for this is made by adding an extra sigma to the specifications-
+/- 4 sigma.
Six Sigma theory involves improving a process to defect levels of parts per 
million.
This requires specifications set at +/- 4.5 sigma units for the short run. In 
the long
run, an allowance of 1.5 sigma is made for drift. Together, these produce 6 
sigma.
The theoretical and practical basis for this theory is covered in the 
training.

Grantblair@aol.com
Ninety Six SC
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