Blog : Difference between Six Sigma and Lean

Discussing how Six Sigma and Lean differ yet compliment each other.

There has been a prolonged debate going on whether Six Sigma or Lean is a better approach in optimising various business processed by removing defects (or waste). Both these approaches have their own pros and cons that may cite different situations where one approach may deliver better results than the other.

There is a third side to this coin as well! Some Experts believe that it is more appropriate to integrate Six Sigma and Lean to offer the most effective and efficient methodology that addresses a range of challenges in optimising the business processes.


Six Sigma Approach

The ultimate goal of Six Sigma is to identify and remove the defects or errors in the process to improve the quality and deliver the efficiency of 99.99966%.

Invented by Motorola in 1986, Six Sigma was used in Manufacturing in its initial days until the practitioners discovered its ability to be applied to the other aspects of the business- from production to management to service delivery to customer satisfaction.

Six Sigma mainly follows DMAIC methodology as-






Today, Six Sigma plays a key role in the leadership of an organization and its wide-scale implementation can help a company to achieve real and measurable results.

The Lean Approach

Alike Six Sigma, Lean is an effective tool that focuses on removing the wastes especially in manufacturing and production processes. It emphasises on keeping only value-adding or value-enabling inputs or steps that are directly contributing in manufacturing the ultimate products.

Lean primarily follows five principals as-

1. Value Stream Mapping

2. Takt Time

3. 5 Why’s and Ishikawa

4. Load Balancing or Heijunka

5. Mistake Proofing or Poka-Yoke

In Lean methodology, value is considered as anything for which the customer is willing to pay and anything that does not contribute to get paid by the customer is considered as non-value adding or waste and hence is removed from the process.

Comparing Six Sigma and Lean

Technically, Six Sigma and Lean, both have the same goal of removing waste or defects from the processes however the fundamental difference is in their respective approaches to define the waste.


The Lean approach believes that the waste comes from the unnecessary steps that do not add value to the process whereas Six Sigma asserts that the waste results from the variation within the process.

Of course, there is truth in both of these assessments, which is why both Lean and Six Sigma methodologies have been so successful in improving overall business performance in a variety of fields. In fact, these two disciplines have proven to be especially successful when working in tandem - hence the creation of Lean Six Sigma.

Applicability of Six Sigma and Lean

The Lean approach is more suitable for Manufacturing and Production Processes whereas Six Sigma is generally believed to be applicable in most of the processes across the industries.

Both these approaches provide you somewhat similar learnings about how the quality to be maintained and hence is being loved by most of the companies across the world.

You can start learning them at any point of time and with e-Six Sigma, you will have the advantage of learning them at your own time-convenience and pace, even on your smartphones! e-Six Sigma empowers you to make the most of it from day 1 by teaching you to save time in learning and we all know that time is money! So don’t waste time aka money and enrol in just a minute at Happy Learning!

Abhijeet Mandlecha
Founder-CEO, e-Six Sigma

An IIM-Alumnus with 12+ years of cross-functional experience. Served at Infosys. Certified Six Sigma Black Belt.