Six Sigma Quality¶

While possibly the most publicized part of Six Sigma, Six Sigma quality is the least important component. In fact, many companies have had successful Six Sigma programs while focusing primarily on costs and schedule. The key is to achieve bottom-line impact. Six Sigma quality is just one possible focus.

Six Sigma quality is a level of defects that corresponds to 3.4 dpmo (defects per million opportunities). This does not mean that the final product is 3.4 dpm. It means that each opportunity is at 3.4 dpm. Most products have many opportunities for defects. Each measurable characteristic represents an opportunity. For example, in extruding plastic tubing there is the inside diameter, wall thickness and cut length. There are other opportunities for defects as well. The quality of the finished product will depend on its complexity. It might range from 50 dpm for simpler disposable products (15 opportunities) to 95% first-time yield for moderately complex hardware (thousands of opportunities).