What is the difference between Six Sigma, Lean and Lean Six Sigma?
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 organisation.
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 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, Analyse, Improve, and Control), which is used to
correct issues in existing processes. The second is DMADV (Define, Measure, Analyse,
Design, Verify), which is used to create new processes.
Lean
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:
| Transport – Moving products & information |
| Inventory – Storing parts, pieces, documentation ahead of requirements |
| Motion – Moving people |
| Waiting – For parts, information, instructions or equipment |
| Over production – Making more than is IMMEDIATELY required |
| Over processing – Tighter tolerances, higher grade materials or additional processing than are necessary |
| Defects – Rework, scrap or incorrect documentation |
| Skills – Underutilising capabilities, delegating tasks with inadequate training |
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.
Lean Six Sigma
Here we have the hybrid methodology that combines the best of both Lean and Six Sigma.
Organisations 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.