Let’s talk about Sigma Quality Level. This is a guide that is used to measure how often the defects will probably occur. We are including a generic table of Sigma Performance Levels, from One to Six Sigma. We’ve outlined the Sigma Level Table below:
This table shows that even when operating at a Sigma 3 or 4 (which is better than most) that is still too high compared to the Six Sigma level. Then it does depend on the product when dealing with Defects Per Unit (DPU).
DPU: Number of defects observed/Number of units inspected
The outcome of the DPMO (Defects Per Million Opportunities) will vary depending on the product. For example, a car would be judged very differently than a bike; this is assuming they both have the same per unit defect rate. The car with so many more parts and a complicated system of operation will obviously have more opportunities for defects than a bike. So, the same DPU might be viewed as lower on a truck than the same DPU on a bike since the bike is a much simpler product.
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