Six Sigma is a highly disciplined and structured framework for delivering an extremely high quality level of product or services. Six Sigma is also a set of tools for statisical analysis for displaying process data, tools for working in teams, tools for project management, and tools for managing change.
The Six Sigma improvement framework specifies five steps that occur in a precise sequence, used for understanding and improving any process, known as DMAIC:
Approach improvement to projects with Lean-Six Sigma methodology
One important change from how improvement projects had been approached previously in general improvement models was simply to more clearly define specific targets to improve. By just more specifically defining the problem in a "problem statement" at the start of the project, the results of improvement projects were greatly improved. This change in approach may seem obvious and simple, yet what had been revealed by previous improvement methodologies in the past has been less successful than planned, and in part simply because the scope of the project was poorly defined in the beginning for both participants and those outside the improvement team. As a result, the "classic" improvement model of the Plan-Do-Check-Act (PDCA) was expanded into a five step improvement methodology which included a DEFINE phase. The define phase has served to help projects to narrow and more precisely define their scope and targets, and this has focused energies on what was really critical for success, as well as doing a much better job of communicating project goals and outcomes to key stakeholders throughout the organization. Now all Six Sigma process improvement projects follow the expanded five step methodology of DMAIC. There are many variations in the application of Lean and Six Sigma tools possible, but the "tool-kit" itself has been well documented and incorporated into a working body of knowledge accessible to everyone at every level of an organization.
The principles of Lean and methods of Six Sigma work together within the DMAIC model. The Six Sigma tools focus primarily on process outputs, and Lean production methods focus on the throughput of a process. Together Lean and Six Sigma work together to help organizations tackle short and long term improvement goals.