What is the difference between Kaizen, Lean & Six Sigma?

What is the difference between Kaizen, Lean & Six Sigma?

Over the years, the terms Kaizen, Lean & Six Sigma have lost their individual identity.

These words are being used interchangeably  without knowing the true meaning or use of these words. I am often asked – by potential clients and friends alike, what is the difference b/w these three words? Often I hear people saying which is the best tool? I am using Lean, I don’t need KAIZEN™ or Six Sigma or vice versa!

What many people fail to realize is that each concept/tool is used to solve specialized problems as opposed to the answer to every problem. Just because you have the tool doesn’t mean you should use it. No tool should be picked up or used until one can properly answer the question “what is the problem we are trying to solve?”

What is Kaizen?

KAIZEN™ is a Japanese word for “Change for the better” or it is also referred to as “Continuous Improvement”. So it is a journey and not a destination, it is a mindset as opposed to being a specific tool. It is a culture that needs to changed & adopted by the organizations. It uses personal creativity and ingenuity to identify problems and then develop and implement ideas to solve those problems. KAIZEN™ philosophy says that everything can be improved and everything can perform better or more efficiently. It helps to identify 3 MU’s – muda (wastes), Mura (variation/ inconsistency) and Muri (strain/ burden on people & machines).

KAIZEN™ is the practice of continuous improvement. KAIZEN™ was originally introduced to the West by Masaaki Imai in his book Kaizen: The Key to Japan’s Competitive Success in 1986. Today KAIZEN™ is recognized worldwide as an important pillar of an organization’s long-term competitive strategy. KAIZEN™ is continuous improvement that is based on certain guiding principles:

·         Good processes bring good results

·         Go see for yourself to grasp the current situation

·         Speak with data, manage by facts

·         Take action to contain and correct root causes of problems

·         Work as a team

·         KAIZEN™ is everybody’s business

·         And much more!

One of the most notable features of KAIZEN™ is that big results come from many small changes accumulated over time. However this has been misunderstood to mean that KAIZEN™ equals small changes. In fact, KAIZEN™ means everyone involved in making improvements. While the majority of changes may be small, the greatest impact may be kaizens that are led by senior management as transformational projects, or by cross-functional teams as KAIZEN™ events.

What is Lean

Lean is opposite to fat and it often focuses on removal of ‘wastes’ sometimes referred to as ‘muda’ in Japanese. Operations that fail to create value for the end customer are deemed “wasteful.”

Although the basic Lean model was introduced more than 100 years ago, it has continued to evolve over time, from Henry Ford’s continuous assembly lines for the Ford Model T, to the concept of interchangeable parts used by Eli Whitney and Samuel Colt, to the Toyota Production System. These concepts, in addition to a multitude of others, have come together to formulate what we know today as Lean manufacturing.

What is Six Sigma

It is a set of tools and strategies to limit defects and variability/ in consistency, also referred to as “Mura” in business processes. Its two project methodologies – DMAIC (define, measure, analyse, improve, control) and DMADV (define, measure, analyse, design, verify) are based on Deming’s Plan-Do-Check-Act cycle. The team leverages advanced statistical techniques such as pareto charts and root cause analysis to reach quantified value targets.

The roots of Six Sigma as a measurement standard can be traced back to Carl Friedrich Gauss (1777-1855) who introduced the concept of the normal curve. Six Sigma as a measurement standard in product variation can be traced back to the 1920’s when Walter Shewhart showed that three sigma from the mean is the point where a process requires correction. Many measurement standards (Cpk, Zero Defects, etc.) later came on the scene but credit for coining the term “Six Sigma” goes to a Motorola engineer named Bill Smith. (Incidentally, “Six Sigma” is a federally registered trademark of Motorola).


KAIZEN™ looks to improve all aspects of a business through standardizing processes, increasing efficiency and eliminating waste by involving everyone while Six Sigma focuses more on improving the quality of the final product by finding and eliminating causes of defects, whether by variances (Sigma is a mathematical term that measures a process' deviation from perfection) in the business process or in manufacturing and Lean focus on elimination of ‘wastes’in order to improve process speed and quality through reduction of process wastes

The most important fact however is that one is not better than the other - you need, can benefit from the use of, and should be using all. The bottom line is don’t waste lots of time and money trying to put ways of thinking and improving in place as these concepts/ tools are designed to save time and money. The ultimate goal will be Operational Excellence for Business Excellence and the spirit should be to improve, to change the paradigms, to change the culture, to change the current set of habits, etc.

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