Six Sigma is a business management strategy originally developed by Motorola, USA in 1986. As of 2010, it is widely used in many sectors of industry, although its use is not without controversy.
Six Sigma seeks to improve the quality of process outputs by identifying and removing the causes of defects (errors) and minimizing variability in manufacturing and business processes. It uses a set of quality management methods, including statistical methods, and creates a special infrastructure of people within the organization ("Black Belts", "Green Belts", etc.) who are experts in these methods. Each Six Sigma project carried out within an organization follows a defined sequence of steps and has quantified financial targets (cost reduction and/or profit increase).
The term Six Sigma originated from terminology associated with manufacturing, specifically terms associated with statistical modeling of manufacturing processes. The maturity of a manufacturing process can be described by a sigma rating indicating its yield, or the percentage of defect-free products it creates. A six sigma process is one in which 99.99966% of the products manufactured are statistically expected to be free of defects (3.4 defects per million). Motorola set a goal of "six sigma" for all of its manufacturing operations, and this goal became a byword for the management and engineering practices used to achieve it.
Six Sigma originated as a set of practices designed to improve manufacturing processes and eliminate defects, but its application was subsequently extended to other types of business processes as well. In Six Sigma, a defect is defined as any process output that does not meet customer specifications, or that could lead to creating an output that does not meet customer specifications.
The idea of Six Sigma was actually “born” at Motorola in the 1970s, when senior executive Art Sundry was criticizing Motorola’s bad quality. Through this criticism, the company discovered the connection between increasing quality and decreasing costs in the production process. Before, everybody thought that quality would cost extra money. In fact, it was reducing costs, as costs for repair or control sank. Then, Bill Smith first formulated the particulars of the methodology at Motorola in 1986. Six Sigma was heavily inspired by six preceding decades of quality improvement methodologies such as quality control, TQM, and Zero Defects, based on the work of pioneers such as Shewhart, Deming, Juran, Ishikawa, Taguchi and others.
Like its predecessors, Six Sigma doctrine asserts that:
* Continuous efforts to achieve stable and predictable process results (i.e., reduce process variation) are of vital importance to business success.
* Manufacturing and business processes have characteristics that can be measured, analyzed, improved and controlled.
* Achieving sustained quality improvement requires commitment from the entire organization, particularly from top-level management.
Features that set Six Sigma apart from previous quality improvement initiatives include:
* A clear focus on achieving measurable and quantifiable financial returns from any Six Sigma project.
* An increased emphasis on strong and passionate management leadership and support.
* A special infrastructure of "Champions," "Master Black Belts," "Black Belts," "Green Belts", etc. to lead and implement the Six Sigma approach.
* A clear commitment to making decisions on the basis of verifiable data, rather than assumptions and guesswork.