A laboratory reports 1000 ED stat results in a month (Product).
10% or 100 results are not reported out within the specified period of time (Defects).
The number of Opportunities for defects is 3, representing the three phases of testing (preanalytical, analytical, and post-analytical phases).
Once the number of products, defects, and opportunities are known, both DPMO and Sigma level can be calculated.
- Defects per opportunity (DPO)= Defect/(Product x Opportunities). Using the data presented in the scenario,
DPO= 100/(1000 X 3) or 0.033333
- Defects per million opportunities (DPMO) Six-Sigma is determined by evaluating the DPMO, Multiply the DPO by one million.
DPMO= 0.33333 X 106 or 33,333
- Process Sigma Once you have determined the DPMO, you can now use a Six Sigma table to find the process sigma. You will look for the number closest to 33,333 under defects per 1,000,000. In this case, the process sigma is ~ 3.3.
A short term Sigma conversion table is available at: http://www.six-sigma-material.com/Tables.html
. Accessed July 21, 2016.