Six Sigma is a data driven, customer focused, and result oriented methodology which uses statistical tools and techniques to systematically eliminate defects and inefficiencies to improve processes. It is a systematic method to measure and analyze business processes to identify critical factors affecting business results, thereby improving processes, and establishing controls around the improved processes.
Six Sigma is a widely accepted quality concept in the corporate world today. Six Sigma started its journey in the 1980s as a data driven method to reduce variation in electronic manufacturing processes in Motorola Inc. in the USA. Six Sigma became famous when Jack Welch made it vital to his successful business strategy at General Electric in 1995. Today it is used as a business performance improvement methodology all over the world in diverse industries such as general manufacturing, construction, banking and finance, healthcare, education, government, KPO/BPO, and IT/Software. At present IT/ ITES sector companies are dynamically implementing Six Sigma and it is no longer just confined to the manufacturing sector.
The term ‘Six Sigma’ comes from statistics and is used in statistical quality control (SQC) which evaluates process capability i.e. the numerical measure of the ability of a process to meet the customer specifications. It originated from terminology associated with manufacturing which refers to the ability of manufacturing process to produce a very high proportion of output within the given specifications. The sigma rating of a process indicates its yield or percentage of defect-free outputs it produces. A Six Sigma process is the one which produces 99.99966% statistically defect-free outputs which is equivalent to 3.4 defects per million opportunities (DPMO).
| Six Sigma Score | Defects per million Opportunities (DPMO) | Percentage |
|---|---|---|
| 2 | 308,537 | 69.15% |
| 3 | 66,807 | 93.32% |
| 4 | 6,210 | 99.38% |
| 5 | 233 | 99.98% |
| 6 | 3.4 | 99.9997% |
Six Sigma uses a set of quality management and statistical methods and creates a team of experts within the organisation (Executive Leadership, Champions, Black Belt, Green Belt, Yellow Belt etc.) having specific skill sets required to carry out a Six Sigma project. Each Six Sigma project carried out within an organisation follows a defined sequence of phases with quantifiable value targets such as reduction in process cycle time, reduced cost, increase in quality rating / customer satisfaction index, and reduction in defect rate.