What is the PPM for a 2 sigma level?

The PPM (parts per million) for a 2 sigma level is approximately 308,770 ppm. In the context of the Six Sigma methodology, sigma levels represent the number of standard deviations a process can operate from the mean before producing defects.

At a 2 sigma level, the process is capable of producing a significant number of defects. Specifically, the statistical calculations indicate that a process operating at 2 sigma has a defect rate of about 30.8%. This translates to roughly 308,770 defective parts per million, indicating that for every million opportunities, about 308,770 will result in a defect.

This level of performance portrays a relatively low capability and highlights the significant room for improvement in quality processes. In other contexts, higher sigma levels correspond to dramatically lower defect rates, which is why 3.4 ppm is famously associated with the Six Sigma level, reflecting exceptional process capability.