The calculation of a Sigma level, is based on the number of defects per million opportunities (DPMO).
In order to calculate the DPMO, three distinct pieces of information are required:
a) the number of units produced
b) the number of defect opportunities per unit
c) the number of defects
The actual formula is:
DPMO = (Number of Defects X 1,000,000)
((Number of Defect Opportunities/Unit) x Number of Units)
A manufacturer of computer hard drives wants to measure their Six Sigma level.
Over a given period of time, the manufacturer creates 83,934 hard drives.
The manufacturer performs 8 individual checks to test quality of the drives.
During testing 3,432 are rejected.
Defects 3432 DPMO 5111.158768
Opportunities 83934 Sigma Level 4.1
Defect Opportunities per unit 8
Six Sigma Table: 1 690,000