Lean Six Sigma is a business improvement methodology. Businesses operate through processes which do things (place an order) or produce things (make a pizza) for customers. By making processes work better, the business’ customers are more satisfied and so the business becomes more successful. Lean Six Sigma is often described as a problem-solving approach because it is built around a root-cause-analysis approach and tools which are geared at solving process problems.

So in a nutshell, Lean Six Sigma solves process problems which makes processes work better so that customers are happier and the business becomes more successful.

Lean Six Sigma is a combination of two methodologies:

• Lean, which focuses on making processes flow more smoothly (faster, more efficient) by removing waste.
• Six Sigma, which focuses on quality – doing everything in the process right first time. This is built on the idea of variation reduction which often involves data analysis so Six Sigma is recognised for promoting the use of data more effectively in the business.

A common misconception is that Lean Six Sigma is only relevant to manufacturing. While Lean and Six Sigma did originate in manufacturing environments, the methodology has been used widely across healthcare, financial services, logistics, government, retail and professional services for more than twenty years. Wherever work is performed through a process, there is an opportunity to improve it using Lean Six Sigma.

Lean Six Sigma is based on a handful of key principles:

• Focus on the customer: understand what customers value and design processes to deliver what they value.
• Understand the process: use process analysis to find the root causes of problems before making changes.
• Reduce waste in the process: eliminate activity that consumes time, effort or resources without adding value.
• Reduce variation in the process: create better-quality products and services.
• Use data to make decisions: use facts and evidence rather than assumptions or opinions.
• Engage the people who do the work: involve those closest to the process in identifying and making improvements.
• Pursue continuous improvement: treat improvement as an ongoing journey rather than a one-off project.

Lean Six Sigma is particularly effective where organisations face recurring challenges such as delays, rework, complaints, quality issues, rising costs or inconsistent performance. Rather than treating symptoms, it helps teams find and address root causes, which is why so many organisations value its structured approach to problem solving. By combining process understanding, data analysis and employee engagement, improvements become measurable, sustainable and aligned to business objectives.

Top Tips

• Lean Six Sigma improves customer experience, quality and employee engagement
• It applies in any industry where work takes place through repeatable processes.
• The aim is to solve business problems, not to apply tools for their own sake.
• The best opportunities are often in processes that frustrate customers or employees.
• Successful Lean Six Sigma initiatives combine technical tools, leadership commitment and employee involvement.

DMAIC is the problem-solving framework within Lean Six Sigma. It stands for Define, Measure, Analyse, Improve and Control. DMAIC provides a structured, project-based approach to improve processes and solve business problems.

It helps organisations avoid a common mistake: implementing solutions before fully understanding the problem. Teams often jump straight to corrective action based on assumptions, only to find the issue returns because the true root cause was never addressed. DMAIC provides a logical approach:

• Define the problem as fully as possible using whatever knowledge about it exists.
• Measure current process performance and build process knowledge using mapping and data techniques.
• Analyse the process and data to identify root causes of the problem.
• Improve the process by implementing and testing solutions targeted at those root causes.
• Control the process so improvements are sustained over time.

DMAIC is most valuable when problems are recurring, complex, data-rich or have several contributing factors; for simpler issues, a lighter-touch approach may be more appropriate. Its key strength is confidence in decision making at every point: choices rest on evidence rather than opinion, which leads to more sustainable, measurable results.

Top Tips

• Spend enough time defining and scoping the problem at the outset.
• Use clear and simple data and process visualisations to ensure common understanding and sustain focus
• Focus on root causes rather than treating symptoms.
• Involve the people closest to the process; they often understand the problem best.
• Don’t overlook Control; many improvements fail because there is no plan to sustain them.

If you face difficult problems, if you face the same problems again and again, if you need to improve but you don’t know how, if you have tried to improve and not succeeded then the answer is yes. Lean Six Sigma is effective against significant and recurring issues that affect performance, customer experience, employee satisfaction or cost: excessive rework, long lead times, bottlenecks, complaints, quality issues, inconsistent service or rising costs. Many organisations know these problems exist but struggle to understand why, and that is exactly the gap the methodology addresses.

This is only a brief introduction. For a fuller look at the symptoms it addresses and how to tell whether it fits your situation, see Common Problems Lean Six Sigma Solves.

Lean Six Sigma is often associated with large-scale transformation, but many successful projects are initiated at the ground level solving invididual business problems. A typical project might reduce customer waiting times, improve service levels, cut errors, improve satisfaction, reduce the time to onboard a new employee, improve order accuracy, speed up responses to enquiries, streamline an approval process or reduce defects in production.

One point is worth absorbing early: success is rarely about the tools alone. A technically perfect solution will still fail if the people affected don’t understand or support it, which is why effective improvement combines the technical method with communication, stakeholder engagement and change management.

This is an overview, the Delivering Improvement page explores how projects are actually run.