The difference between lean and six sigma

You often hear the terms “lean” and “six sigma” used together, as in lean six sigma experts or lean six sigma methodologies. While these two concepts complement each other and are often applied in combination, they are fundamentally different approaches to process improvement.

Lean vs. six sigma: understanding the core differences

Both lean and six sigma focus on improving efficiency and quality, but they do so in distinct ways:

Lean: eliminating waste

Lean is centred on reducing waste in processes. It identifies and eliminates non-value-adding activities to streamline operations and maximise efficiency. The goal is to create faster, more responsive workflows by minimising delays, excess inventory, unnecessary movement, and other inefficiencies.

Key principles of lean include:

• Identifying and removing waste (overproduction, waiting time, defects, etc.)

• Continuous improvement (kaizen) to refine processes over time

• Enhancing value delivery to customers by optimising workflows

Six sigma: reducing variation

Six sigma, on the other hand, focuses on reducing process variation and ensuring consistency. By using data-driven methodologies and statistical analysis, six sigma aims to reduce defects and deviations from a defined standard, leading to higher-quality outputs.

Core elements of six sigma include:

• The DMAIC framework (define, measure, analyse, improve, control) for problem-solving

• Statistical tools to measure and control process performance

• A focus on reducing variability to improve reliability and predictability

By the way the belt certification (e.g. white, yellow, green, black) is only referring to six sigma and officially not the lean part. However, a six sigma blackbelt will have a deep understanding of most lean tools.

Why are lean and six sigma used together?

While lean and six sigma are different, they are often combined because they address complementary aspects of operational efficiency. Lean improves speed and efficiency by cutting waste, while six sigma enhances quality and consistency by reducing defects. Together, they provide a holistic approach to continuous improvement.

Organisations that integrate lean and six sigma benefit from:

• Faster, more efficient processes with reduced waste

• Higher-quality outputs with fewer defects

• A structured, data-driven approach to operational excellence

How can we help you?

Understanding the differences between lean and six sigma allows businesses to apply the right tools to the right challenges, ensuring sustainable improvements in efficiency and quality. Whether you need to streamline operations, improve consistency, or integrate both methodologies, we can help.

Our expertise in lean and six sigma enables us to guide you in implementing tailored strategies that deliver measurable results. Get in touch with us today to explore how we can support your continuous improvement journey