Six Sigma at many organizations simply means a measure of quality that strives for near perfection. Six Sigma is a disciplined, data-driven approach and methodology for eliminating defects (driving towards six standard deviations between the mean and the nearest specification limit) in any process — from manufacturing to transactional and from product to service.
The statistical representation of Six Sigma describes quantitatively how a process is performing. To achieve Six Sigma, a process must not produce more than 3.4 defects per million opportunities.
Different definitions about Six Sigma from around the web are as follows:
- Six Sigma TerminologyA methodology that provides businesses with the tools to improve the capability of their business processes.
- Process Improvement Glossary –A method or set of techniques. Six Sigma is generally used to indicate that a business process is well controlled.
- Circuit City – In 2001 Six Sigma was introduced as an initiative within Circuit City’s annual report.  Six Sigma is applied to Circuit City’s operational side such as supply chain and distribution centers.
- Tamworth Quality Services – This is a complete system of quality management originating in the USA, but now becoming popular in the UK.
- Wikipedia – Six Sigma is a business management strategy, originally developed by Motorola, that today enjoys wide-spread application in many sectors of industry. Six Sigma seeks to identify and remove the causes of defects and errors in manufacturing and business processes.
- Quality Glossary – A failure rate of 3.4 parts per million or 99.9997%
- Glossary of terms and definitions – A set of practices first created by Motorola that attempts to systematically remove imperfections in manufacturing processes while improving quality and efficiency; also, a set of practices that specifies the mathematical precision of measurements.
- eMJA Glossary – A systematic method for improving the operational performance of an organisation by eliminating variability and waste (“sigma” stands for standard deviation from the mean in a normal distribution).
- Mayo Medical Laboratories – A statistical concept that represents the amount of variation present relative to customer requirements or specifications.
- Industry Forum – A ‘measure of goodness’ involving the application of statistical methods to business processes to improve operating efficiency, reduce variation, avoid defects and reduce waste.
- Pulse – It is a methodology to manage process variations that cause defects and to systematically work towards managing variation to eliminate those defects. The objective of Six Sigma is to deliver world-class performance, reliability, and value to the end customer.
- Obis Omni – A quality management program to achieve “six sigma” levels of quality. Pioneered by Motorola in the mid-1980s, it aims to have the total number of failures in quality, or customer satisfaction, occur beyond the sixth sigma of likelihood in a normal distribution of customers.
- Lean Manufacturing Glossary – Six Sigma is a statistical term that equates to 3.4 defects per one million opportunities. Typical manufacturers operate at around three sigma, or 67,000 defects per million. Six Sigma can achieve dramatic improvement in business performance through a precise understanding of customer requirements and the elimination of defects from existing processes, products and services. Key tenets of Six Sigma: Define, Measure, Analyze, Improve, Control. To fully embrace Six Sigma, an organization must work intimately with all internal disciplines in addition to external suppliers and customers.
- Qmi Solutions – A methodology and set of tools used to reduce quality problems to less than 3.4 defects per million or better.
- ISSEL – A quality management and process improvement methodology particularly well-suited to process-intensive industries like manufacturing. Six Sigma measures a given process by its average performance and the standard deviation (or variation) of this performance, aiming to reduce the occurrence of defects in a given process to a level of “”Six Sigma”outside the norm; no more than 3.4 times per million.