Both Six Sigma and Kaizen are techniques used to make business improvements. These systems are both designed to be used continuously in order to make positive changes as time goes on. Both systems are developed around the idea that everything – from specific processes to entire companies – can be improved and made to work more efficiently.


The biggest difference between Kaizen and Six Sigma is that Kaizen is used to improve the company as a whole, whereas Six Sigma involves recognizing and correcting deviations in a product.

What is Kaizen?

Kaizen is a Japanese word that means "change for the better," though the process is also referred to as "continuous improvement." The Kaizen philosophy was first introduced to Westerners in 1986 by Masaaki Imai, who explained that Kaizen means everything can be improved and made to be better or perform more efficiently. In order to do this, the process aims to identify the three "Mu's:" Muda (meaning wastes), Mura (meaning variations and inconsistencies) and Muri (meaning strains and burdens placed on people and machines). The guiding principles of Kaizen include:

  • Good processes are required to bring good results
  • Go see for yourself to understand the current situation
  • Manage by facts and speak with data
  • Take action to stop and fix the root causes of problems
  • Work as a team when possible
  • Kaizen isn't just for managers, but everyone

Kaizen isn't so much a tool to use to improve things, but instead, a philosophy that relies on the personal ingenuity of everyone in the company to solve problems. Kaizen involves making many small, incremental changes as time goes on, which will slowly, but surely improve the business as a whole.

What is Six Sigma?

When it comes to differences between Six Sigma and Kaizen, it's important to recognize that while Kaizen is a philosophy to improve the company as a whole, Six Sigma is a set of tools and strategies that can limit defects and inconsistencies in a product or service using hard data. This is done through two project methodologies:

  • DMAIC: define, measure, analyze, improve and control
  • DMADV: define, measure, analyze, design verify

Under both methodologies, the team should use statistical techniques in order to define quantified value targets.

Which is Best for You?

A lot of people mistakenly believe they should only use only Kaizen or Six Sigma, but these two methods are actually best used together. You can also use the Lean methodology, which focuses on eliminating waste by recognizing and reducing any part of the product creation process that fails to create value for the customer. Lean focuses on seven areas where wastes can kill business efficiency:

  • Transport
  • Inventory
  • Motion
  • Waiting
  • Overproduction
  • Over-processing
  • Defects

In fact, you might have the best results for your whole business when you combine Lean, Six Sigma and Kaizen methodologies in order to make your business as effective and profitable as possible. That's because, in a way, Lean and Six Sigma both help move forward the Kaizen philosophy. After all, Kaizen is a philosophy without specific tools that seeks to eliminate Muda (wastes), Mura (inconsistencies) and Muri (strains and burdens), while Lean is a targeted approach to reduce Muda, including inconsistencies, and Six Sigma is a data-driven technique to get rid of Mura. Of course, Lean and Six Sigma only look at your products or services and don't focus on the company as a whole, so it is important to still seek ways to reduce Muda and Mura outside of your production process.