Six Sigma Principles

Organizations use Six Sigma principles to improve quality, decrease costs, and better meet customer needs. In the book "The Six Sigma Way", define Six Sigma as "a comprehensive and flexible system for achieving, sustaining and maximizing business success. Six Sigma is uniquely driven by close understanding of customer needs, disciplined use of facts, data, and statistical analysis, and diligent attention for managing, improving, and reinventing business process".

Six Sigma's target for perfection is the achievement of no more than 3.4 defects, errors, or mistakes per million opportunities. This target number is explained in more detail later in this section. An organization can apply the Six Sigma principles to the design and production of a product, a Help Desk, or other customer-service process.

Projects that use Six Sigma principles for quality control normally follow a five-phase improvement process called DMAIC (pronounced de-MAY-ic), which stands for Define, Measure, Analyze,Improve, and Control. DMAIC is a systematic, closed-loop process for continued improvement that is scientific and fact based. The following are brief descriptions of each phase of the DMAIC improvement process:

1. Define: Define the problem/opportunity, process, and customer requirements. Important tools used in this phase include a project charter, a description of customer requirements, process maps, and Voice of the Customer (VOC) data. Examples of VOC data include complaints, surveys, comments, and market research that represent the views and needs of the organization's customers.
2. Measure: Define measures, then collect, compile, and display data. Measures are defined in terms of defects per opportunity.
3. Analyze: Describe process details to find improvement opportunities. A project team working on a Six Sigma project, normally referred to as a Six Sigma team, investigates and verifies data to prove the suspected root causes of quality problems and substantiates the problem statement. An important tool in this phase is the Fishbone or Ishikawa diagram.
4. Improve: Generate solutions and ideas for improving the problem. A final solution is verified with the project sponsor, and the Six Sigma team develops a plan to pilot test the solution. The Six Sigma team reviews the results of the pilot test to refine the solution, if needed, and then implements the solution where appropriate.
5. Control: Track and verify the stability of the improvements and the predictability of the solution. Control charts are one tool used in the control phase.