Some Six Sigma practitioners are concerned about the current method used to calculate Z-scores and express process capability. A proposed modification, based on Berryman’s scorecard, may fill the need for a more intuitive and business savvy metric.
In order for any process capability to accurately be calculated, one must properly define and quantify the process defect, unit and opportunity of a customer CTQ. This article defines the three terms, as well as provides examples.
Although customer survey data is often used to determine the degree of customer satisfaction, it is worthwhile to consider recorded complaints data in order to calculate the number of actual complainers and the number of possible complainers.
Calculating your process sigma can be accomplished in 5 simple steps: Define your opportunities, define your defects, measure your opportunities and defects, calculate your yield, look-up process sigma. This article includes all the tools you need.
Practitioners must learn when and how to calculate the sigma level of a process.
When learning about Six Sigma, it may help to consider these charts, which detail how sigma level relates to defects per million opportunities (DPMO), and some real-world examples.
It can be difficult to assess an overall sigma level because some critical processes are more important than others. One approach is to weight each of the critical processes when calculating overall sigma level.
The use of slogans such as "zero defects" to spur quality can be counterproductive, detracting attention from the tried-and-true tools and culture associated with successful Six Sigma programs.