Six Sigma is a set of tools and techniques used to process improvement. It looks to improve the quality of the output of a process by finding and removing the causes of defects, as well as minimising variability in business and manufacturing processes.
Using a set of quality management methods – mainly practical, statistical methods – Six Sigma creates an infrastructure of people within the organisation who are experts in the methods.
Each Six Sigma project carried out follows defined steps and has specific value targets, such as reduce process time, reduce pollution, reduce costs, increase customer satisfaction and increase profits.
The term was initially registered as a Motorola trademark, due to terminology associated with statistical modelling of manufacturing processes. A Six Sigma process is one in which 99.99966% of all opportunities to produce a feature of a part are statistically expected to be free of defects, which works out at around 3.4 defective features per million opportunities. Motorola set a target of “Six Sigma” for all of its manufacturing operations, which soon became a by-word for the management and engineering practices used to achieve it.