For those new to Six Sigma, the terminology can get confusing. Before getting too deep into trying to learn the methodology, it’s important to know exactly which one you should be working with.

There are three main methodologies: Six Sigma, Lean and Lean Six Sigma. Understanding the differences between the three can help you determine which one is right for you and your organization.

The following presents an overview of each.

Six Sigma

Six Sigma is the original process improvement methodology. It was first used by Motorola in manufacturing. Since then, it’s use has spread to almost every industry. Continuous process improvement is a universal need.

Six Sigma focuses on reducing variance and errors in a production process. That’s because processes without consistent dependability eventually lead to errors and defective products. Reducing variance leads to higher quality products and services.

The goal is to reduce the defects to 3.4 per one million opportunities. That is the Six Sigma standard.

Six Sigma offers different belt classifications for those who learn the methodology. In order of depth of knowledge, they are White Belt, Yellow Belt, Green Belt, Black Belt and Master Black Belt.

There are two primary methods in Six Sigma. Both use data-driven, fact-based approaches to identifying and eliminating defects in a process.

The first is DMAIC (define, measure, analyze, improve, and control), which is used to correct issues in existing processes. The second is DMADV (define, measure, analyze, design, verify), which is used to create new processes.


Like Six Sigma, Lean focuses on process improvement. However, Lean focuses on attacking waste.

In Lean, any activity that does not add value to the end user of the product or service needs to be eliminated. There are eight main areas where Lean looks to eliminate waste:

  • Defects in a process
  • Overproduction
  • Waiting or idle time between operations
  • Non-utilized talent (not making use of skills employees bring to the table)
  • Wasteful transportation practices
  • Excess inventory
  • Unnecessary actions by employees or machines
  • Extra processing, or steps that do not add value

While first designed for manufacturing, Lean works across all industries and in all types of operations. Rather than focusing on one point in a process, Lean requires optimizing a process as it flows through the various technologies, assets and departments before reaching customers.

This emphasis on the entire flow of the process, rather than just isolated points, goes beyond eliminating waste and works to create a culture of continuous improvement across a whole organization that also empowers employees.

Eventually, this dedication to eliminating waste leads to more efficient organizations that make better products.

Different methodologies

Lean Six Sigma

Here we have the hybrid methodology that combines the best of both Lean and Six Sigma. Organizations began turning to this idea when they realized they had issues in areas the separate approaches handle.

Essentially, those who use Lean Six Sigma seek to eliminate waste in ways defined by Lean while also seeking to improve processes by putting DMAIC and DMADV in place.

Combined, the two methodologies help companies become more efficient across all operations while also creating better quality products and services.

The right one to choose depends on the needs of an organization. But the above outlines where and how the three methodologies are used. Despite the differences, they are all designed to increase a company’s competitive advantage. Those with knowledge in Lean, Six Sigma and Lean Six Sigma are in position to take a lead role in implementing needed changes.

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