Six Sigma

Six Sigma is a set of techniques and tools for process improvement, developed originally by Motorola in the 1980s. It is a data-driven approach and methodology for eliminating defects in any process, from manufacturing to transactional and from product to service. The central idea behind Six Sigma is to improve the quality of process outputs by identifying and removing the causes of defects and minimizing variability in manufacturing and business processes.

Six Sigma uses a set of quality management methods, including statistical methods, and creates a special infrastructure of people within the organization (such as “Black Belts” and “Green Belts”) who are experts in these methods. The methodology is represented by the DMAIC process (Define, Measure, Analyze, Improve, Control) for existing processes and DMADV (Define, Measure, Analyze, Design, Verify) for new processes or products.

The term “Six Sigma” comes from statistics and is used in statistical quality control, which evaluates process capability. It refers to the ability of processes to produce a very high proportion of output within specification. Processes that operate with “six sigma quality” are expected to produce defect levels below 3.4 defects per million opportunities (DPMO). Six Sigma’s goal is to improve overall processes to that level of quality or better.