Difference between Lean and Six Sigma

KEYWORD: Lean Manufacturing

There has been an ongoing debate among the businesses, practitioners, and theoreticians on which method, Lean, or Six Sigma is better for cutting costs, eliminating wastes, and gaining better returns on investments. It is of significance to know the fundamental differences between the two. So that, it is possible to choose the right one or a mixture of them that is suitable for your business. We aim to achieve this in this article.

Lean manufacturing originated with Henry Ford who wanted to keep the production standards very high to achieve, which he sought to eliminate wastes at each stage. However, it became popular after the Lean process develops by the Toyota Production System, (TPS), with which it became synonymous.

On the other hand, Six Sigma concentrates more on the approach by seeking to achieve uniformity in the process output through the definition of problems, identification of defects, variations in order to achieve quality.

Both Lean and Six Sigma are compared below with each other in terms of various parameters. It may be noted that both of them were propounded in the year 1980.


A. Goal


Removal of wastes and improving the process flow.

Six Sigma:

Removal of the variations in the processes and improving the process capability.

B. Focus


Towards flow, cost, speed, and time. From the time an order to the time the eventual shipment takes place, the production cycle is shortened by focusing on the elimination of wastes at every stage.

Six Sigma:

Towards the identification of problems, locating defects and variations, and achieve quality. Prevention of defects takes place by reducing variation, centering in processes until the quality,  which the customers expect is met.

C. Tools


Kaizen-5S and 8 Wastes.

Value stream mapping

Six Sigma:

Control Charts, which undertake definition with a checklist containing measurement, analysis with which improvements are brought about and kept under control.

D. Methods


Adopts a ‘Plan-do-Check-Act’ approach to specify the value in terms of what is important from the point of view of the customers, identify the values stream by putting in place what comprises of the entire value stream, and determine the flow of the material and information through the entire production processes.

Applies the pull concept by asking as to how the customers can be let with pulling the products rather than pushing them and while doing so optimize the processes.

Six Sigma:

Define, measure, analyze and improve control for sustaining quality

Define what is important, measure how is it done, analyze what is wrong, apply what needs to do, and control the output by sustaining improvements.

F. Benefits


The flow reduces through the application of the flow time reduction method.

Improvement in production achieves through increasing the efficiency in processes.

Six Sigma:

Paves the way for undertaking evidence-based decisions by quantifying the root causes of variations with which sustainable solutions are found.

This makes it possible to quantify the financial benefits, as a result of which the focus directs towards bringing specific improvements and improving the bottom line.

In conclusion, it stated in a nutshell that both Lean and Six Sigma have similar goals in that they both seek to eliminate wastes by putting in place efficient systems. The difference sees in each of them being different in their approaches to achieving the overall goal. Which is due to the reason that each one identifies the root causes of waste in a different manner. Even though there will always be a tendency on the part of those engaged in supply chain operations to compare Lean Vs. Sigma. Both of them comprise effective tools to find solutions and create an environment that could reduce costs, improve quality and enhance productivity.   It is possible for you to derive maximum utility if you combine them in a judicious manner.

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