Six Sigma

What Is Six Sigma?

Generally, Six Sigma is a problem-solving methodology that helps enhance business and organizational operations. It can also be defined in a number of other ways:

  • A quality level of 3.4 defects per million opportunities
  • A rate of improvement of 70 percent or better
  • A data-driven, problem-solving methodology of Define-Measure-Analyze-Improve-Control
  • An initiative taken on by organizations to create bottom-line breakthrough change

Six Sigma Principles

Six Sigma is based on a handful of basic principles, and these principles create the entire Six Sigma arrangement. Here are Six Sigma’s fundamental principles:

  • Y = f(X) + å: All outcomes and results (the Y) are determined by inputs (the Xs) with some degree of uncertainty (å).
  • To change or improve results (the Y), you have to focus on the inputs (the Xs), modify them, and control them.
  • Variation is everywhere, and it degrades consistent, good performance. Your job is to find it and minimize it!
  • Valid measurements and data are required foundations for consistent, breakthrough improvement.
  • Only a critical few inputs have significant effect on the output. Concentrate on the critical few.

The Six Sigma Scale

The Six Sigma scale shows how well a vital feature performs compared to its requirements. The higher the sigma score, the more efficient the feature is. This table shows the universal Six Sigma scale:

Sigma Level (Z) Defects per Million Opportunities (DPMO) Percent Defects (%) Percent Success (Yield %) Capability (CP)
1 691,462 69 31 0.33
2 308,538 31 69 0.67
3 66,807 6.7 93.3 1.00
4 6,210 0.62 99.38 1.33
5 233 0.023 99.977 1.67
6 3.4 0.00034 99.99966 2.00

The DMAIC Method of Six Sigma

The DMAIC (Define-Measure-Analyze-Improve-Control) project method is a formalized problem-solving process of Six Sigma. It’s made-up of five steps to apply to any procedure of a business to improve effectiveness.

  1. Define: Set the context and objectives for your improvement project.
  2. Measure: Determine the baseline performance and capability of the process or system you’re improving.
  3. Analyze: Use data and tools to understand the cause-and-effect relationships in your process or system.
  4. Improve: Develop the modifications that lead to a validated improvement in your process or system.
  5. Control: Establish plans and procedures to ensure that your improvements are sustained.

The Tools-Methods Landscape of Six Sigma

Having the right tools and knowing how to apply them to your Six Sigma projects will help you produce accurate, acceptable, and reusable outcomes.