Process fallout quantifies how many defects a process produces and is measured by Defects Per Million Opportunities (DPMO) or PPM. The below Process Fallout table provides the process yield and the relationship to measures of process fallout against the six sigma levels ranging from 1 through 6 in terms of long and short sigmas. A process with a compliance of six sigma level has the process yield of 99.9999998% accuracy and a defect of 0.002 DPMO/PPM.
| Short Sigma Relationship | ||||
|---|---|---|---|---|
| Cpk | Sigma level (σ) | Area under the probability density function | Process yield | Process fallout (in terms of DPMO/PPM) |
| 0.33 | 1 | 0.6826894921 | 68.27% | 317311 |
| 0.67 | 2 | 0.9544997361 | 95.45% | 45500 |
| 1.00 | 3 | 0.9973002039 | 99.73% | 2700 |
| 1.33 | 4 | 0.9999366575 | 99.99% | 63 |
| 1.67 | 5 | 0.9999994267 | 99.9999% | 1 |
| 2.00 | 6 | 0.9999999980 | 99.9999998% | 0.002 |
| Long Sigma Relationship | ||||
|---|---|---|---|---|
| Cpk | Adjusted Sigma level (σ) | Area under the probability density function | Process yield | Process fallout (in terms of DPMO/PPM) |
| 0.33 | 1 | 0.3085375387 | 30.85% | 691462 |
| 0.67 | 2 | 0.6914624613 | 69.15% | 308538 |
| 1.00 | 3 | 0.9331927987 | 93.32% | 66807 |
| 1.33 | 4 | 0.9937903347 | 99.38% | 6209 |
| 1.67 | 5 | 0.9997673709 | 99.9767% | 232.6 |
| 2.00 | 6 | 0.9999966023 | 99.99966% | 3.40 |
In relationship to measures of process fallout, the process yield is the complement of PPM which is equal to the area under the probability density function when its output is distributed normally.
