Six Sigma is a highly disciplined approach that enables us to focus on creating and delivering nearly-perfect products and services. The underlying idea being that if you can measure how many "defects" you have in a process, you can systematically figure out a way to eliminate them and get as close to "zero defects" as possible. This concept is the motivating factor why employers today are increasingly searching for candidates with this type of certification.
Originally developed by Bill Smith at Motorola in 1986, the Six Sigma Training program was created using some of the most innovative quality improvement methods from the preceding six decades. The term "Six Sigma" is derived from a field of statistics known as process capability. The term 6 Sigma refers to the ability of manufacturing processes to produce a very high proportion of output within specification. Processes that operate with "six sigma quality" over the short term are assumed to produce long-term defect levels below 3.4 defects per million opportunities. Six Sigma's goal is to improve overall processes to that level of quality or better.
