Is Six Sigma the only way to improve?

When training and coaching Six Sigma professionals, one of the topics that I encourage folks to think about is whether or not Six Sigma is the only path that should be followed by an organization that is seeking to improve their operations.  In our Green Belt program I ask students to choose one side or the other of this issue and then debate the subject.  One side of the argument is that Six Sigma is the “one true way” to improve, while the con position is that there are multiple paths to improvement.

Early in my consulting career I was hired by a prestigious Six Sigma consulting organization to develop a Lean training program, equivalent in depth and breadth to their Six Sigma Black Belt.  Their intent was to offer Lean as an alternative to smaller organizations that were not willing or able to support a full blown Six Sigma deployment.  At that time I was considered to be an expert in Lean but was not certified at any level in Six Sigma.

Early in the development process I presented an overview of Lean to a group of Six Sigma Black Belts.  Their reaction to my presentation was very interesting.  Their mantra was “We don’t need lean because we have Six Sigma.  We can call any problem a defect, and we can fix any defect with Six Sigma”.

As an example, setup time reduction is one of the tools and techniques of Lean.  There is a well understood methodology in Lean for analyzing and reducing the time it takes to change from producing one product to another.  The Black Belts said “We don’t need the Lean approach.  We will just call long setup time a defect and then improve it using the Six Sigma approach”.   They used the same argument over and over during my presentation.  Anything Lean can do, we can do better.

My reaction was that this group of Black Belts was limiting themselves to looking at problems from only one perspective.  They were zealots who believed that their way was the only way.  The Six Sigma Black Belts impressed me as believing that “We can call anything a nail, and then we can hit the nail with our Six Sigma hammer”.

An analogy that I use in the classroom is diet and exercise.  There are many diets and many exercise programs.  Pick a combination of diet and exercise and stick to it and you will lose weight.  Which approach you use is not nearly as important as your level of dedication to using a given approach.   The same is true with process improvement.

A mechanic with a large box of tools will use the tool that is most appropriate for the task at hand.  My belief, based on many years of experience and application in the field of process improvement, is that there is plenty of room for the use of a blended approach to process improvement in most organizations.   In our courses I teach the use of the Theory of Constraints to identify where to focus improvement efforts, Lean to identify and eliminate waste, and Six Sigma to systematically reduce variation.  The result is improvement to customer satisfaction, reduction of operating cost, and improved profitability.

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About the author:  Mr. Roger C. Ellis is an industrial engineer by training and profession.  He is a Six Sigma Master Black Belt with over 45 years of business experience in a wide range of fields.  Mr. Ellis develops and instructs Six Sigma professional certification courses for Key Performance LLC.   For a more detailed biography, please refer to