What is Lean, Six Sigma and Lean Six Sigma?

Aiming to provide the insight on the difference between the term “Lean”, “Six Sigma” and “Lean Six Sigma”, this article highlights the meaning of each term and unpack the characteristics of each methodology.

15 November 2021

What is Lean, Six Sigma and Lean Six Sigma?

What is Lean?

Lean was introduced as production methodology that focuses on a business’ internal need to maximize value-added activities (which customers would pay for) and the reduction of waste that increases the cost of running a business. It was popularized by the Toyota Production Systems. The Lean approach focuses on increasing the process speed through the elimination of complexities and utilizing tools that analyze process flows, constraints and time delays at each step of the process. It also focuses on identifying value-added and value-enabling activities through the elimination of non-value adding activities known as waste.

The modern Lean production additionally focuses on improving process flow by addressing the imbalance (in resources or materials) and creating a production level that acts as a “pull process”.

What is Six Sigma?

Six Sigma usually finds its way into an organization as a quality improvement method due to its reputation of using statistical tools to measure quality and precision of a product or service.

Since its conception in the early 80s. Six Sigma has evolved from a mere statistical quality improvement technique into an established methodology that provides businesses with a comprehensive toolset to improve the capability of business processes and quality of products and services.

Six Sigma emphasized on the need for improvement in business performance that leads to minimizing defects, for example, not meeting a customer’s specification or specific service requirement. In addition, Six Sigma also addresses variation in process and in quality that deters that capability of consistently producing high quality products and services.

Terminologies synonymous to Six Sigma include:-


The DMAIC Cycle

(Define-Measure-Analyze-Improve-Control) – as problem solving roadmap (see figure 1.2)

The DMAIC Cycle
Figure 1.2: The DMAIC Cycle


The measure of DPMO

(Defects per Million Opportunity) – A measure of process performance & quality based on non-conformance to a quality specification.


The Voice of Customers (VOC)

A method utilized to determine a customer’s wants and needs that is organized and structured with key measures and metrics to establish and evaluate quality standards.

What is Lean Six Sigma?

Lean Six Sigma is a methodology driven by the need to change, to continuously improve and eliminate complexities, and to meet the goals of the business and shareholders through a single crucial element – the Voice for the Employee, or simply put, organizational effectiveness.

Lean Six Sigma Strategy
Figure 1.3: Lean Six Sigma Strategy

Here’s A Little Recap

And now that we’ve unpacked all three, it’s time to do some recap!

Lean is a production methodology that maximizes value-added activities and focuses on reducing waste. Six Sigma on the other hand, is a quality improvement method which measures the quality and precision of a product or service. By combining these two essential components of business process improvement, we can achieve organizational effectiveness with Lean Six Sigma. Lean Six Sigma is a problem-solving and change-driven methodology that can maximize the shareholder’s return.

Recap of Lean, Six Sigma & Lean Six Sigma
Figure 1.4: Recap of Lean, Six Sigma & Lean Six Sigma

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