Comparison of performance improvement at different sigma levels
Why six sigma?
Does 99.9% yield is good enough for an organization?
With 99.9 % yield, we say the organization operates at 4 to 5 Sigma level. Taking into account some real world examples, with 99.9 % yield, we come across the following example scenarios which are surely unacceptable in customer’s point of view :
- Unsafe drinking water almost 15 minutes each day
- 5400 arterial by pass failures each year
- Visas issued to 50 dangerous persons each year
By moving to Six Sigma level with 99.9997% yield, significant improvements have taken place resulting in very high quality with almost nil defects and very good customer satisfaction as shown below :
- Unsafe drinking water only few seconds a day
- 18 arterial bypass failures
- No visas issued to dangerous persons
The following real world examples explain the importance and need for achieving six sigma level quality.
| Comparison of performace improvement with 99.9% and 99.9997 acceptence | ||
| Scenarios | 99.9% acceptance (Sigma Level : 4 to 5 Sigma) |
99.9997 % acceptance (Sigma Level : 6 Sigma) |
| Arterial bypass failures in an year | 5400 | 18 |
| Commercial aircraft take off aborted each year | 31,536 | 107 |
| Train wrecks a year | 180 | < 1 |
| Visa issued to dangerous persons | 50 | none |