A management framework, originally invented by Motorola, that aims at maximizing the quality of an organisation's end products by identifying and eliminating sources of defects and reducing variability, until processes produce less than 3.4 defects per million opportunities for deviation.

Six Sigma uses statistical methods and the DMAIC / DMADV methodologies to systematically analyse and improve existing or new processes.

With the framework's increasing popularity, the expression "Six Sigma" also evolved to designate a business philosophy focused on meeting customer needs, and sustaining and developing the organization's products and processes using a disciplined data-driven approach to improvement.

see also: dmadv methodology