The Six Sigma process is a methodology for process improvement developed by a scientist at Motorola in the 1980s . It is a quality-control methodology that businesses use to significantly reduce defects and improve processes . The term “six sigma process” comes from the notion that if one has six standard deviations between the process mean and the nearest specification limit, as shown in the graph, practically no items will fail to meet specifications . Six Sigma practitioners use statistics, financial analysis, and project management to achieve improved business functionality and better quality control by identifying and then correcting mistakes or defects in existing processes . The five phases of the Six Sigma method, known as DMAIC, are defining, measuring, analyzing, improving, and controlling .
Lean Six Sigma is a team-focused managerial approach that seeks to improve performance by eliminating waste and defects while boosting the standardization of work . It combines Six Sigma methods and tools and the lean manufacturing/ lean enterprise philosophy, striving to reduce the waste of physical resources, time, effort, and talent while assuring quality in production and organizational processes .