Six Sigma vs Lean Six Sigma: What’s the Difference?

Six Sigma vs Lean Six Sigma: What’s the Difference?

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Syed Aquib Ur
Syed Aquib Ur Rahman
Senior Executive Content
Updated on Jul 8, 2022 14:50 IST

For professionals who are looking to start a career in quality management or operations, Six Sigma or Lean Six Sigma are the few certifications that pop up in the mind. Six Sigma and Lean Six Sigma are two different tracks, which often leads to the confusing question – which certification is the best suited for you? This article will help you to understand the difference between Lean Six Sigma and Six Sigma.


Let’s jump in:

About Six Sigma

Six Sigma (6σ) is a disciplined, data-approach methodology to eliminate defects in any process — manufacturing to transactional and product to service. This approach was first developed by two engineers, Bill Smith & Mikel J Harry, working at Motorola in 1986. The goal of Six Sigma is very specific, which is to reduce defect rates in any process, and uses one of the two approaches – DMAIC (Define, Measure, Analyse, Improve and Control) or DMADV (Define, Measure, Analyse, Design, and Verify).

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About Lean Six Sigma

The evolution of business processes is a common thing so as to adapt to modern technology and demands. Six Sigma is no different and with the combination of lean management methods, it was developed into an approach that focuses on both process speed and quality.

Lean Six Sigma also uses the DMAIC approach as Six Sigma and has the same organisational structure: Yellow Belt, Green Belt, Black Belt, and Master Black Belt.

Six Sigma vs Lean Six Sigma

Though there are not many differences between the approaches in Six Sigma and Lean Six Sigma, let us look at the main areas where they both stand out to be distinct:

  • The main difference is that Lean is a philosophy and Six Sigma is a program. Six Sigma does not attempt at organisational culture change while Lean attempts at reorganising the culture and behaviour among the employees. Thus, Lean Six Sigma is both a program and a philosophy that attempts both.
  • The focus in Six Sigma is the elimination of errors or defects, which can hinder the ability to deliver high-quality services. The idea of Six Sigma is to reinvent the process so as to limit the process variations to 3.4 defects per million

Lean Six Sigma focuses both on the elimination of waste and speeding up of the process. There are 8 type of wastes according to the lean system: Waiting, Overproduction, Rework, Motion, Over Processing, inventory, Intellect and Unnecessary. It works to reduce the process variation, resulting in a quicker cycle of iterative improvements.

In simple, the focus of Six Sigma is on the customer and the end product, while Lean Six Sigma focuses on waste and production methods.

  • If you are an experienced professional and have supported quality improvement projects, Six Sigma Green Belt is good for you. However, if you do not have any experience, you can go for Lean Six Sigma Green Belt as it has no prerequisites. You can learn the Six Sigma DMAIC process and other areas in Lean Six Sigma.
  • When it comes to ownership, there’s a marked difference in Six Sigma and Lean Six Sigma. In Six Sigma, the onus of implementation falls on special-purpose teams formed specifically for the purpose. On the other hand, Lean Six Sigma requires adoption by the entire process members as it aims at continuous improvement across the entire value stream of operations.

Six Sigma vs Lean Six Sigma | Choosing the Right Certification

There is no single body that offers Six Sigma certification and it varies according to the organisation’s guidelines. Also, there is a certain amount of confusion regarding the level of certification.

  • The right accreditation body – Always make sure that the certification body is recognised by leading global organisations and bodies. There are two main accreditation bodies that are recognised across the globe: the American Society for Quality (ASQ) and International Association for Six Sigma Qualification (IASSC).
  • The right level of certification – There are four levels of certification as mentioned above. You have to check out which certification is the best for you. Go through the prerequisites and eligibility for each certification before choosing the right one.


Six Sigma or Lean Six Sigma? It all comes down to your organisational practice and which area you feel will be important to improve your organisation’s process. If you want to learn the best of both Lean and Six Sigma, you can go for a Lean Six Sigma course.

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About the Author
Syed Aquib Ur Rahman
Senior Executive Content

Aquib is a seasoned wordsmith, having penned countless blogs for Indian and international brands. These days, he's all about digital marketing and core management subjects - not to mention his unwavering commitment ... Read Full Bio