Six sigma, or 6Q, is both methodology for process improvement and a statistical concept that seek to define the variation inherent in any process. The overarching premise of Six Sigma is that variation in a process leads to opportunity for error; opportunities for error then lead to risks for products defects. Product defects-whether in a tangible process or service-lead to poor customer satisfaction. By working to reduce variation and opportunities for error, the Six Sigma method ultimately reduces process costs and increases customers satisfaction.

In applying Six Sigma, organization, teams, and project managers seek implement strategies that are based on measurement and metrics. Historically, many business leaders decision based on intuition or experience. Despite some common beliefs in various industries, Six Sigma doesn't remove the need for experienced leadership, and it doesn't negate the importance of intuition in any process. Instead, Six Sigma works alongside other skills, experience, and knowledge to provide a mathematical and statistical foundation for decision making. Experience might say a process isn't working; statistics prove that to be true. Intuition might guide a project manager to believe a certain change could improve output; Six Sigma tools help organizations validate those assumption.

Without proper measurement and analysis, decision making processes in an organization might proceed as follows:

Someone with clout in the organization has a good idea or takes interest in someone else'idea. Based on past experience or knowledge, decision makers within an organization believe the idea will be successful. The idea is implemented; sometimes it is implemented in beta mode so expenses and risks are minimized. The success of the idea weighed after implementation; problems are addressed after they impact products or processes in some way in the present or the future.