What is the difference between 3 and 6?

What is the difference between 3σ and 6σ?

Most companies have been following a standard of performance for 3σ. There is nothing wrong with 3σ for certain products and certain industries. However, there is a tremendous difference between 3σ and 6σ. For example, a 3σ capability accounts for 93.32 percent long-term yield (this is the historical standard for most organizations). By comparison, a 4σ accounts for 99.38 percent long-term yield (this is a standard that some organizations operate currently). If an organization wants to account for 99.99966 percent long-term yield, then the move to 6σ is inevitable. When the 6σ philosophy is implemented, expect your organization to perform at 3.4 defects per million opportunities. That is truly a breakthrough in performance! The percentages presented here have been adjusted for the long-term shift.