Six Sigma originates from a 19th Century mathematical theory, but found its way into today’s mainstream business world through the efforts of an engineer at Motorola in the 1980s. Now heralded as one of the foremost methodological practices for improving customer satisfaction and improving business processes, Six Sigma has been refined and perfected over the years into what we see today.

No matter the setting, the goal remains the same: Six Sigma seeks to improve business processes by removing the causes of errors that lead to defects in a product or service. It accomplishes this by setting up a management system that systematically identifies errors and provides methods for eliminating them.

Those who learn Six Sigma practices achieve designations at each level of accomplishment, including Green Belt, Black Belt, Master Black Belt and Champion.

The Beginnings of Six SigmaSix Sigma Symbol

The process that led to Six Sigma was originated in the 19th Century with the bell curve developed by Carl Fredrick Grauss. In the 1920s, statistician Carl Shewhart, a founding member of the Institute of Mathematical Statistics, showed that a process required correction after it had deviated three sigma from the mean.

Move forward to the 1970s, when Motorola senior executive Art Sundry complained about the lack of consistent quality in the company’s products, according to the 2006 book “Six Sigma” by Richard Schroeder and Harry Mikel.

According to the accepted story from numerous sources, Motorola engineer Bill Smith eventually answered the call to consistently manufacture quality products by working out the methodologies of Six Sigma in 1986. The system is influenced by, but different than, other management improvement strategies of the time, including Total Quality Management and Zero Defects.

Some of the Major Aspects of Six Sigma

In an effort to bring operations to a “six sigma” level – essentially 3.4 defects for every one million opportunities – the methodology calls for continuous efforts to get processes to the point where they produce stable and predictable results.

Deconstructing the manufacturing process down to its essential parts, Six Sigma defines and evaluates each step of a process, searching for ways to improve efficiencies in a business structure, improve the quality of the process and increase the bottom-line profit.

Toward that end, the methodology calls for the training of personnel in Six Sigma, including beginner Green Belts, Black Belts who often head up individual projects, and Master Black Belts who look for ways to apply Six Sigma across a business structure to make improvements.

The ultimate goal is to improve every process to a “six sigma” level or better. Does it work? Motorola reported in 2006 that the company had saved $17 billion using Six Sigma.

Methodologies of Six Sigma

There are two major methodologies used within Six Sigma, both of which are composed of five sections, according to the 2005 book “JURAN Institute Six Sigma Breakthrough and Beyond” by Joseph A. De Feo and William Barnard.

DMAIC: This method is used primarily for improving existing business processes. The letters stand for:

  • Define the problem and the project goals
  • Measure in detail the various aspects of the current process
  • Analyze data to, among other things,  find the root defects in a process
  • Improve the process
  • Control how the process is done in the future.

DMADV: This method is typically used to create new processes and new products or services. The letters stand for:

  • Define the project goals
  • Measure critical components of the process and the product capabilities
  • Analyze the data and develop various designs for the process, eventually picking the best one
  • Design and test details of the process
  • Verify the design by running simulations and a pilot program, and then handing over the process to the client

There are also many different management tools used within Six Sigma. While there are too many to list, here are details on a few of them.

Five Whys – This is a method that uses questions to get to the root cause of a problem. The method is simple: simply state the final problem (the car wouldn’t start, I was late to work again today) and then ask the question “why,” breaking down the issue to its root cause. In these two cases, it might be: because I didn’t maintain the car properly and because I need to leave my house earlier to get to work on time. The process first came to prominence at Toyota.

CTQ Tree – The Critical to Quality Tree diagram breaks down the components of a process that produces the features needed in your product and service if you wish to have satisfied customers.

Root Cause Analysis – Much like the Five Whys, this is a process by which a business attempts to identify the root cause of a defect and then correct it, rather than simply correcting the surface “symptom” of the problem.

Ultimately, all of the tools and methodologies in Six Sigma serve one purpose: to streamline business processes in order to produce the best products and services possible with the smallest amount of defects. Its adoption by corporations around the globe is both an indicator of and testament to its remarkable success in today’s business environment.

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