What Is Six Sigma?

Six Sigma is a quality-control methodology developed in 1986 by Motorola, Inc. The method uses a data-driven review to limit mistakes or defects in and process. Six Sigma emphasizes cycle-time improvement while at the same time reducing manufacturing defects to a level of no more than 3.4 occurrences per million units or events. In other words, the system is a method to work faster with fewer mistakes.

Six Sigma points to the fact that, mathematically, it would take a six-standard-deviation event from the mean for an error to happen. Because only 3.4 out of a million randomly (and normally) distributed, events along a bell curve would fall outside of six-standard-deviations (where sigma stands in for "standard deviation").

In recent years, Six Sigma has evolved into a more general business-management philosophy, focused on meeting customer requirements, improving customer retention, and improving and sustaining business products and services. Six Sigma applies to all industries. Many vendors, including Motorola itself, offer Six Sigma training with the special certifications carrying the names of yellow belt, green belt and black belt.

Key Takeaways

  • Six Sigma is a quality-control methodology developed in 1986 by Motorola, Inc.
  • It was originally developed as a management a method to work faster with fewer mistakes.
  • It has now become an industry standard with certifications offered to practitioners.


The Basics of Six Sigma

Six Sigma represents a management ideology which focuses on statistical improvements to a business process. It advocates for qualitative measurements of success over qualitative markers. Therefore, practitioners of Six Sigma are those business people who use statistics, financial analysis and project management to achieve improved business functionality.

Six Sigma evolved to define numerous ideas within the business sphere and is sometimes confusing. First, it's a statistical benchmark. Any business process which produces less than 3.4 defects per 1 million chances is considered efficient. A defect is anything produced outside of consumer satisfaction. Second, it is a training and certification program which teaches the core principles of Six Sigma. Practitioners may achieve the Six Sigma certification belt levels, ranging from white belt to black belt. Finally, it's a philosophy which promotes the idea that all business processes can be measured and optimized.

The Five Steps of Six Sigma

True believers and practitioners in the Six Sigma method follow an approach called DMAIC which stands for define, measure, analyze, improve and control. It is a statistically driven methodology that companies implement as a mental framework for business process improvement. The ideology behind DMAIC is that a business may solve any seemingly unsolvable problem by following the DMAIC steps.

  1. A team of people, led by a Six Sigma champion, defines a faulty process on which to focus, decided through an analysis of company goals and requirements. This definition outlines the problem, goals and deliverables for the project.
  2. The team measures the initial performance of the process. These statistical measures make up a list of potential inputs which may cause the problem and help the team understand the process's benchmark performance.
  3. Then the team analyzes the process by isolating each input, or potential reason for the failure, and testing it as the root of the problem. Through analysis, the team identifies the reason for process error.
  4. From there, the team works to improve system performance.
  5. Finally, the team adds controls to the process to ensure it does not regress and become ineffective once again.

Lean Six Sigma is a team-focused managerial approach that seeks to improve performance by eliminating waste and defects. It combines Six Sigma methods and tools and the lean manufacturing/lean enterprise philosophy, striving to reduce waste of physical resources, time, effort and talent while assuring quality in production and organizational processes. Under the tenets of Lean Six Sigma, any use of resources that does not create value for the end customer is considered a waste and should be eliminated.

Real World Example

As reported by TheVoiceCalifornia.com, in Ventura County, California, the county is crediting the use of Lean Six Sigma for a savings of US$43 million. The local government begin to use the program on a county-wide level in 2008 and have trained more than 5,000 employees on employing the methodology. The county states the savings are coming from hard budget items which no longer need funding as well as savings in employee hours.