What is Six Sigma?
Generally, Six Sigma is a set of techniques and tools that help businesses improve their processes. It’s a problem-solving methodology that helps enhance business and organizational operations. It can also be defined in a number of other ways:
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A quality level of 3.4 defects per million opportunities
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A rate of improvement of 70 percent or better
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A data-driven, problem-solving methodology of Define-Measure-Analyze-Improve-Control
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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:
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Y=f(X) + ε: All outcomes and results (theY) are determined by inputs (theXs) with some degree of uncertainty (å).
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To change or improve results (the Y), you have to focus on the inputs (theXs), modify them, and control them.
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Variation is everywhere, and it degrades consistent, good performance. Your job is to find it and minimize it!
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Valid measurements and data are required foundations for consistent, breakthrough improvement.
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Only a critical few inputs have significant effect on the output. Concentrate on the critical few.
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Every decision and conclusion has risk (ε), which must be weighed against the context of the decision.
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.
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Define: Set the context and objectives for your improvement project.
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Measure: Determine the baseline performance and capability of the process or system you’re improving.
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Analyze: Use data and tools to understand the cause-and-effect relationships in your process or system.
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Improve: Develop the modifications that lead to a validated improvement in your process or system.
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Control: Establish plans and procedures to ensure that your improvements are sustained.
The tools and methods 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. Here’s an overview of the Six Sigma landscape:
