The question seems so obvious that you might be afraid to ask it: What are the differences between Lean and Six Sigma? For many, understanding these differences is the first step on the journey into successful continuous process improvement.

As noted in CFO magazine, it’s easy to get caught up in the buzzwords surrounding the two methodologies and lose sight of the fact they are well-thought-out philosophies that can help organizations change their culture for the better.

The Short Version

Both Lean and Six Sigma had their starts in manufacturing. They have since spread around the world and have been adopted by a number of industries.

Six Sigma helps reduce variance in a process, eliminating the errors that cause defects in a product or service. The term “Six Sigma” refers to reaching a state where there are about 3.4 defects for every one million opportunities.

Lean offers tools and techniques that focus on eliminating waste. Every aspect of an operation is considered in detail, with processes that add value separated from non-value adding processes that do not serve the end user (the customer).

Both are part of continuous process improvement. The term continuous is important, because smart leaders recognize that you never stop improving, especially in a changing, dynamic and competitive modern business world.

Both methods are typically put to use by project teams that are led by professionals who hold a Six Sigma belt.

The Belt System

Even someone who has taken a casual look at Six Sigma likely has seen references to belts. These colored belts indicate the level of knowledge and skill a person has in understanding the theories of Six Sigma and applying it to real-world situations.

White Belt – This is the most basic level. It provides the fundamentals, allowing those who earn the belt to promote its use in their area.

Yellow Belt – Yellow Belts assist on Six Sigma project teams. They may help create process maps or gather data to be analyzed. They understand the fundamental tools and techniques and how to apply them to projects in a supporting role. Offering Yellow Belt training can prove a key to success in an organization because it can help employees – regardless of department – speak the same language.

Green Belt – Green Belts do much of the work on a project and understand the use of Lean and Six Sigma to improve a process. Usually contributing to a project under the instruction of a Black Belt leader, a Green Belt will likely spend between 25% and 50% of their time on projects.

Black Belt – Generally the leader on a project team, Black Belts are considered experts in Lean and Six Sigma. Becoming a Black Belt typically requires successfully leading two projects and passing a certification exam.

Master Black Belt – The Master Black Belt is the highest belt designation and demonstrates mastery of Six Sigma tools and techniques and the ability to successfully lead enterprise-wide projects. The Master Black Belt designation typically requires at least five years of experience as a Black Belt, the completion of at least 10 Six Sigma projects and passing a certification exam.

More on Six Sigma

Six Sigma focuses on examining a process to find errors that are leading to defects in the product or service.

The usual goal is to reduce variability and promote consistency. Consistent processes lead to a reduction in errors. That level of dependability is the goal of Six Sigma.

Both Lean and Six Sigma have many tools and techniques that are deployed to attain the project goal. In Six Sigma, there are two data-driven methods that provide the backbone of the methodology.

  • DMAIC – This approach stands for define, measure, analyze, improve and control. It is used to identify and correct errors in an existing operation.
  • DMADV – This approach stands for define, measure, analyze, design and verify. It is used in the creation of new processes, products or services.

More on Lean

Lean focuses on identifying and eliminating waste in an operation. It involves mapping out an operation in detail to find where there are issues, then considering every aspect of the operation through the eyes of the end user. Does it benefit them? Does it give them a better product? If not, it needs to be eliminated.

There are eight areas of waste identified in Lean. Wastes tend to fall within one of these categories:

  • Defects – Errors in processes that lead to low-quality products and services
  • Overproduction – Making more of a product than is demanded by end users
  • Waiting – Idle time between two tasks within a process
  • Non-utilized talent – Not leveraging all the talent you have on your team
  • Excess inventory – Wasting space having to house excess inventory
  • Transportation – Non-streamlined transportation leads to wasted time and money
  • Unnecessary actions – Sometimes called “wasted motion,” it refers to employees or machines having to do actions that don’t benefit the process
  • Extra processing – Doing more than what is necessary, wasting time on steps that do not add value

Lean and Six Sigma become more fascinating when you get into the details of the techniques and tools they offer. You can also combine the two (Lean Six Sigma) into a hybrid methodology that helps companies better approach the issues faced in their organization.

Continued success across many industries support the argument that if you want more efficient operations, you should at least consider Lean and Six Sigma training.