What is Six Sigma?

Six Sigma is a process improvement methodology that focuses on eliminating waste and defects while also improving services and products.

It’s easy to see why it remains popular with businesses around the world. What organization doesn’t want those results?

Success has something to do with Six Sigma’s popularity as well. Engineers at Motorola get credit for first creating the tools used in the methodology in the 1980s. They were searching for methods to eliminate defects in the company’s manufacturing processes. By drawing on 19th-century mathematical theories, specifically the bell curve, they were able to propagate some methods and tools to use for Six Sigma.

Six Sigma Success

Six Sigma essentially means refining a process until there are only 3.4 defects per one million opportunities. The methods of Six Sigma helped Motorola reach record-breaking profits. They also, according to the company, saved $17 billion from 1986 to 2008.

What started in manufacturing soon made its way into other areas of industry. Today, Six Sigma and associated methodologies – such as Lean Six Sigma – are used in software, healthcare, media and transportation companies. Nonprofit organizations and even some government agencies also have implemented the methodology.

Companies that use Six Sigma include:

  • Amazon
  • Bank of America
  • Caterpillar
  • Credit Suisse
  • Ford
  • General Electric
  • Boeing
  • 3M

Branches of the United States military also have incorporated Six Sigma, including the Army, Marines and Air Force.

How Does Six Sigma Work?

The first step in making Six Sigma work is buy-in at the executive level. Without that support, the system cannot work.

Education and training of employees is another essential step. Part of the methodology calls for training both leaders and employees in Six Sigma, which result in distinct levels of certification designated by belt colors. They include White, Yellow, Green, Black and Master Black Belt.

Getting buy-in is not always easy. One common criticism of Six Sigma is that it is “just common sense.” But of course, if making efficient and non-wasteful systems proved just a matter of common sense, every business and government would run that way.

Six Sigma provides a framework for making desired goals a reality. The emphasis is on continuous improvement. Eventually, any process can be transformed into one that produces consistent, quality results.

Main Methodologies

Six Sigma provides a wealth of methods and tools to accomplish the goals of improved efficiency and better-quality results. Two of the main methodologies are DMAIC and DMADV. Here is an overview of both.


This methodology is most frequently used to improve existing operations. The acronym stands for define, measure, analyze, improve, control. They are used as follows:

  • Define the exact nature of the defect in the process as well as the ultimate goal
  • Measure in detail every aspect of the process
  • Analyze the resulting data to find what root causes are leading to the defect
  • Improve the process using this information
  • Control the process to ensure changes are maintained and sustainable, and continue to produce the desired results


This methodology is typically used in the design of a new process, usually in relation to creating a new product or service. The acronym stands for define, measure, analyze, design, verify. They are used as follows:

  • Define the goal of the new process
  • Measure in detail every aspect of the proposed new process
  • Analyze the resulting data and create assorted options for creating the process, eventually choosing the best one
  • Design the new process
  • Verify the design through testing and creation of pilot projects before the final process is initiated

Six Sigma Certification

To work most effectively with Six Sigma, employees throughout an organization should become trained in Six Sigma methodology. Employees can earn Six Sigma certification at various levels.

  • White Belt: Offers a basic understanding of Six Sigma methods and terminology
  • Yellow Belt: Works part-time on Six Sigma project teams, typically in an assistant role to those with higher belt levels
  • Green Belt: Assists Black Belts on project teams, has thorough knowledge of Six Sigma methods
  • Black Belt: Has mastered Six Sigma methodologies and leads project teams
  • Master Black Belt: This level is attained by earning a Black Belt and leading many project teams, gaining the experience to develop strong leadership and quantitative skills

Benefits of Six Sigma

Six Sigma methodology provides many benefits for an organization, including identifying inefficiencies in a process and providing the tools to eliminate defects. Reducing waste and cutting costs are a huge benefit. Another outcome is better products and services, as well as improved customer service.

Employees also benefit. Many Six Sigma strategies require employees to learn about the methodology, then apply it to their section of the overall operation. Many of the benefits from Six Sigma derive from these employee efforts.

Six Sigma ultimately represents opportunity. Organizations have an opportunity to work more efficiently and with fewer mistakes. Employees have an opportunity to hone their skills through Six Sigma training and by participating on project teams.

Ultimately, customers benefit the most, with improved products and services.

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