Different sigma levels correspond to different defect rates.
The following are common sigma levels and their corresponding defect rates:
1. Six Sigma:
The Six Sigma level is the highest level of quality, and it corresponds to a very low defect rate of about less than 3.4 defects per million opportunities. defects per million opportunities. This means that at Six Sigma levels, processes are virtually defect-free.
2. Five Sigma:
The Five Sigma level corresponds to a defect rate of about less than 233 defects per 100,000 opportunities. Although slightly lower than Six Sigma, it still represents an extremely high level of quality.
3. Four Sigma:
The Four Sigma level corresponds to a defect rate of approximately less than 6,210 defects per 10,000 opportunities. This level still represents high quality, but there may be some room for improvement.
4. Three Sigma:
Three Sigma level corresponds to a defect rate of approximately less than 66,870 defects per 1,000 opportunities. This level implies that quality needs to be improved and that there may be issues that need to be addressed.
5, Two Sigma (Two Sigma):
Two Sigma level corresponds to a defect rate of about less than 308,537 defects per 100 opportunities. This level indicates a high number of quality problems that require significant improvement.
6. One Sigma:
The One Sigma level corresponds to a defect rate of approximately less than 691,462 defects per ten opportunities. This is the lowest level that implies a quality problem serious enough to require urgent improvement.
It's important to note that different industries and organizations have different standards for what defect rates are acceptable. In some high-risk or demanding industries, such as medical device manufacturing or aerospace, a higher level of quality may be required, and therefore higher levels of Six Sigma or Five Sigma may be pursued. In some other areas, four sigma or lower levels may be sufficient.