Six Sigma Methodologies

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
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.