If that sounds too general, consider what skills are taught:

  • How to define a problem properly
  • How to measure the current performance of a process
  • How to look at a process from the customer’s point of view
  • How to drill down to the root cause of the problem
  • How to come up with solutions to problems
  • How to implement solutions effectively
  • How to measure the new performance of the process
  • How to make sure your new process is controlled

So where does ‘Lean’ and ‘Six Sigma’ fit into all this?

Well actually, they are two different methodologies that do similar and complimentary things.


Let’s start with Six Sigma first – Six Sigma is a statistics-based approach to improving a process. It’s a quality management approach, where we measure everything that can be measured with a relentless focus on quality. Eliminating defects and errors and striving for perfection in the key tenants of Six Sigma.

Six Sigma is also where we get the term ‘belts’ to describe the different levels of knowledge. It’s generally accepted that there are 4 belts and 6 different levels. These are:

  • White Belt – Introduction to Lean Six Sigma
  • Yellow Belt – Awareness of Lean Six Sigma methodology
  • Green Belt – Ability to practice improvement using tools and techniques
  • Black Belt – Expert is tools and techniques, training and mentoring others
  • Master Black Belt – Master of all techniques, training, mentoring, & leadership
  • Champion – Leader of change in an organisation

The Lean Six Sigma Green Belt is the first level where people are trained to actually use the tools and techniques – to apply them in the real world to real problems.

Now let’s talk about Lean. This methodology comes to use courtesy of a global academic study of the Motor Industry – and how there was one company (Toyota) that had a completely different approach to process and performance. These differences were distilled into a book in which they coined the term ‘lean’. Over the years, lots of great tips, tools, techniques and practices have come from this methodology – which looks at processes form the customers’ point of view and is centred around 5 key principles – Value, Values Stream, Flow, Pull and Perfection.

When did these 2 methodologies come together?

Well, they are not officially together – the people who created Lean didn’t get together with the people who created Six Sigma and say, you know what – we should hook up.

Six Sigma as we know it was launched in the 80s and Lean in the 90s. During the 00s people started to refer to themselves as Lean and Six Sigma experts – and over time the ‘and’ was dropped to be simply, Lean Six Sigma experts. You’d be hard-pressed to find someone these days who only referred to themselves as a Lean Expert or a Six Sigma Expert.

This is because the methodologies are not the same – but they are complimentary. There is a large amount of overlap between the 2 methodologies but the reason they work well together is they focus on different things to achieve similar outcomes.

Someone smarter than me once said:

“Lean is looking at a process an inch deep and a mile wide, whilst Six Sigma is looking at a process an inch wide and a mile deep”

It’s a great description for highlighting their differences. Lean focuses on looking at the end to end value stream of a process – importantly looking at the customer experience. They look at the Flow of the process overall and the Pull from the customer. It’s a very wide view of a process usually looking at a select amount of data.

Six Sigma looks at improving a part of a process – but analyses everything about it to figure out the true performance and how it can be incrementally improved.

Together – Lean Six Sigma is a powerful set of ideas and knowledge that can help people improve any process.

Lean Six Sigma Green Belt training is about equipping individuals with the knowledge and understanding to begin applying these ideas in the real world. If you’re looking to make a significant impact on improving your processes, training colleagues to a Lean Six Sigma Green Belt level is definitely the way forward.