# Six Sigma For Dummies

From Six Sigma For Dummies, 2nd Edition by Craig Gygi, Bruce Williams, Stephen R. Covey (Foreword by) [with Neil DeCarlo]

To apply Six Sigma to your business and produce the best results, you need to understand what Six Sigma is, the principles of Six Sigma, and the DMAIC problem-solving method. The correct tools and use of the Six Sigma scale and methods will keep your data dependable and reusable.

## 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) + ε: All outcomes and results (theY) are determined by inputs (theXs) with some degree of uncertainty (å).

• To change or improve results (the Y), you have to focus on the inputs (theXs), 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.

• 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.

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. Here’s an overview of the Six Sigma landscape: