The core differences between Lean and Six Sigma

It is common to have confusion between Lean Manufacturing and Six Sigma, even more, when it comes to the Lean Six Sigma application.

Although Lean and Six Sigma are business methodologies aimed at improving efficiency and effectiveness in organizations, there are theoretical and practical distinctions between them.

These methodologies were created in different contexts and used specific tools to create an efficient and variation-free workflow.

There is a difference between Lean and Six Sigma, but they can also form a powerful set for implementing improvements.

In this article, you will understand these differences and how you can use both in your company.

Six Sigma Methodology

Naturally, the methodology has evolved a lot since its inception until today. This evolution is continuous, and Six Sigma began to be applied in several companies and several businesses.

Through this evolution, the number of tools that the Six Sigma methodology uses has increased. Several features were tested, and today it is possible to understand which ones work best.

This natural evolution was also linked to technological evolution, as today there are several software for analyzing statistical data.

Six Sigma Philosophy

Over time, the Six Sigma methodology was gaining ground among US companies and industries, until Jack Welch, CEO of General Electrics, bought the idea.

He implemented the Six Sigma methodology at GE and had a fantastic result in terms of earnings. So Jack Welch made a huge advertisement for 6 Sigma to the world, expanding the methodology far beyond US limitations.

What is Six Sigma?

The Six Sigma methodology is a management system. Quantitative, as it works with data-based statistics. Structured, as it uses the DMAIC method. And disciplined, as it requires a minimum time of dedication due to a good result.

This methodology works with three main goals, which are: cost reduction, optimization of products and processes, and increase in customer satisfaction.

If you apply Six Sigma in initiatives that involve these goals, you will always be able to work on projects that deliver greater profitability and better results for companies.

Perhaps you might be thinking that the application of this philosophy is only for complex issues. There are Six Sigma projects to reduce travel accommodation costs, reduce fixed costs such as electricity bills, water bills, among others.

What is Lean Manufacturing?

Lean Manufacturing, whose translation is Lean Manufacturing, is an operational philosophy that involves the analysis of the 8 Lean wastes in the production line, line optimization, and continuous improvement with the application of the 7 quality tools.

In other words, this methodology aims to eliminate processes and activities that do not add value to the customer.

With a reduction in waste and an increase in process efficiency, Lean achieves a significant reduction in the time between customer order and delivery (Lead Time), which results in a reduction in the costs involved.

With it, you will find all the historical background necessary to understand the essence of the Six Sigma methodology. From the beginning of its concepts until reaching the present moment.

What is the difference between Six Sigma and Lean Manufacturing?

The difference is that while Six Sigma works to reduce process variability and defects to make it more effective, Lean aims to make the process more efficient by reducing waste and increasing production speed.

The difference between Lean and Six Sigma lies in the approach each methodology uses to avoid failure, eliminate waste and achieve better results.

Lean Manufacturing focuses on streamlining production time to generate more efficiency and less waste. Six Sigma focuses on eliminating defects and extra costs in processes to achieve higher customer approval rates.

Knowing the difference between the two methodologies, it is possible to verify that both can be complementary within a company.

As they address different but interconnected points, the benefits of having these quality tools are numerous.


From a theoretical perspective, an important distinction between Lean and Six Sigma is how practitioners of these methods identify waste. In Lean, waste is a process or activity that does not add value to the customer. In Six Sigma, waste results from variation within a process.

This means that Lean professionals focus on optimizing processes to create value. While Six Sigma proponents aim to eliminate defects and waste by reducing variability, it looks to create value.

History of the tools

The modern practices of Lean and Six Sigma were born in complex production environments – specifically, in the manufacturing of automobiles in Japan. As Western manufacturers began to adopt the practices and principles used by Japanese manufacturers, different versions of Lean evolved. developed.

Lean and Six Sigma share the same ultimate goal: both seek to eliminate waste and increase system efficiency as much as possible. However, since the definition of the root cause of waste differs between these two methods, the approach to achieving this goal also differs.

Mindset vs. Practice

A key difference between Lean and Six Sigma is that Lean is a mindset. Thus, it is a set of principles that, when applied, allows smarter decision-making.

Lean applies the continuous improvement method to continually identify ways to increase value and eliminate waste. Anyone can be a Lean thinker. Lean is more effective when it’s embedded in an organization’s culture and applied from scratch.

Six Sigma is a program: a methodical, structured approach to dealing with organizational problems, eliminating variability, and reducing risk. One of the most recognized elements of Six Sigma is its certification system.

There are Six Sigma professionals at all levels of the organization, each with distinct roles and responsibilities. Here is a basic summary of Six Sigma certifications:

1. Black Belt

Leads problem-solving projects. Trains and trains project teams.

2. Green Belt

Helps in data collection and analysis for Black Belt projects. Leads Green Belt projects or teams.

3. Master Black Belt

Trains and trains Black Belts and Green Belts. It works more at the Six Sigma program level, developing key metrics and strategic direction. Acts as a technologist and internal Six Sigma consultant for the organization.

4. Yellow Belt

Participates as a member of the project team. Reviews process improvements that support the project.

5. White Belt

May work on local problem-solving teams that support general projects, but may not be part of a Six Sigma project team. Understand the basics of Six Sigma from an awareness perspective.


With these different certifications, Six Sigma provides a structured, hierarchical model for leadership that is suitable for highly structured organizations.

Certification programs prepare Six Sigma professionals to play a specific role in your organization. Often starting with localized problem solving, working to lead complex problems and training project teams.

Lean allows for a little more fluidity, encouraging all professionals to think big and solve organizational problems.  However, it doesn’t matter if they are an individual contributor or an executive.

While it can be successful in more structured environments, Lean is well suited for flatter, more autonomous organizational structures that allow for collaboration across departments and levels of management.

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