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Six Sigma is a set of techniques and tools for process improvement. It was introduced by engineer Bill Smith while working at Motorola in 1986. Jack Welch made it central to his business strategy at General Electric in 1995.〔(【引用サイトリンク】 url=http://www.pqa.net/ProdServices/sixsigma/W06002009.html )〕 Today, it is used in many industrial sectors. Six Sigma seeks to improve the quality of the output of a process by identifying and removing the causes of defects and minimizing variability in manufacturing and business processes. It uses a set of quality management methods, mainly empirical, statistical methods, and creates a special infrastructure of people within the organization, who are experts in these methods. Each Six Sigma project carried out within an organization follows a defined sequence of steps and has specific value targets, for example: reduce process cycle time, reduce pollution, reduce costs, increase customer satisfaction, and increase profits. The term ''Six Sigma'' originated from terminology 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 all opportunities to produce some feature of a part are statistically expected to be free of defects (3.4 defective features per million opportunities), although this defect level corresponds to only a 4.5 sigma level. Motorola set a goal of "six sigma" for all of its manufacturing operations, and this goal became a by-word for the management and engineering practices used to achieve it. ==Doctrine== Six Sigma doctrine asserts: * Continuous efforts to achieve stable and predictable process results (e.g., by reducing process variation) are of vital importance to business success. * Manufacturing and business processes have characteristics that can be measured, analyzed, controlled and improved. * 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 clear commitment to making decisions on the basis of verifiable data and statistical methods, rather than assumptions and guesswork. The term "six sigma" comes from statistics and is used in statistical quality control, which evaluates process capability. Originally, it referred 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 (DPMO). Six Sigma's implicit goal is to improve all processes, but not to the 3.4 DPMO level necessarily. Organizations need to determine an appropriate sigma level for each of their most important processes and strive to achieve these. As a result of this goal, it is incumbent on management of the organization to prioritize areas of improvement. "Six Sigma" was registered June 11, 1991 as . In 2005 Motorola attributed over US$17 billion in savings to Six Sigma. Other early adopters of Six Sigma include Honeywell (previously known as AlliedSignal) and General Electric, where Jack Welch introduced the method.〔(【引用サイトリンク】 url=http://scm.ncsu.edu/public/facts/facs030624.html )〕 By the late 1990s, about two-thirds of the Fortune 500 organizations had begun Six Sigma initiatives with the aim of reducing costs and improving quality. In , some practitioners have combined Six Sigma ideas with lean manufacturing to create a methodology named Lean Six Sigma. The Lean Six Sigma methodology views lean manufacturing, which addresses process flow and waste issues, and Six Sigma, with its focus on variation and design, as complementary disciplines aimed at promoting "business and operational excellence".〔 Companies such as GE, Verizon, GENPACT, and IBM use Lean Six Sigma to focus transformation efforts not just on efficiency but also on growth. It serves as a foundation for innovation throughout the organization, from manufacturing and software development to sales and service delivery functions. The International Organization for Standardization (ISO) has published in 2011 the first standard "ISO 13053:2011" defining a Six Sigma process.〔(【引用サイトリンク】 title=ISO 13053:2011 )〕 Other "standards" are created mostly by universities or companies that have so-called first-party certification programs for Six Sigma. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「six sigma」の詳細全文を読む スポンサード リンク
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