Lean vs Six Sigma: Differences between Lean and Six Sigma

Lean vs Six Sigma: Differences between Lean and Six Sigma

You probably would have heard the debate on whether Lean and Six Sigma are the same. This argument has been on for some time now. Some people argue that Lean and Six Sigma are basically the same. On the other hand, others believe that Lean and Six Sigma are two different concepts.

What is the truth then? Are both concepts the same or different? Well, as usual, we will do justice to this topic.

Now, let’s take a look at the following to see if we can find any difference between Lean and Six Sigma.

Table of Contents

Focus of Lean and Six Sigma

One characteristic of eagles is that they focus on their prey from a distance. Focus gives direction, purpose, and clarity. Bearing this in mind, it is important to know the focus of Lean and Six Sigma. This will give us a clue as to what Lean and Six Sigma are about.

Focus of Lean

Lean manufacturing (often referred to as Lean) is an approach for eliminating waste. Waste here is anything that does not add value to your product or service. In other words, anything a customer or stakeholder is not willing to pay for is considered a waste.

In essence, the focus of Lean is to eliminate any form of waste thereby increasing efficiency, speed, and productivity.   

Focus of Six Sigma

Having known the focus of Lean, let’s talk about Six Sigma. Six Sigma is an approach that is driven by data. It focuses on reducing mistakes in processes. The goal of Six Sigma is to reduce errors to the minimum.

The minimum is defined thus: ‘for every one million opportunities, they shouldn’t be more than three errors.’

Want to know more about the focus of Lean and Six Sigma? Please, visit our ‘What is Lean Six Sigma’ page to learn more. 

History of Lean and Six Sigma

I’m sure you now know what Lean and Six Sigma are about. To further understand the difference, let’s look at the histories of both Lean and Six Sigma. 

History of Lean

Lean manufacturing can be traced to the pre-20th century. However, Henry Ford of the well-known Ford Motor Company started Lean manufacturing in the early 1900s. He was the first person to integrate an entire production process. He named this ‘flow production’.

During the 1930s, Kiichiro Toyoda and some other guys working at Toyota looked at Ford’s invention and sought ways to improve on it. The guys at Toyota, therefore, came up with well-known concepts such as Toyota Production System (TPS), Just In Time (JIT), Pull concept, and Jidoka, among others.

Since then, Toyota has continued to make tremendous successes in sales. Their success has spurred many to research further on ‘Lean thinking’. 

History of Six Sigma

I guess you know how it feels when you face a tough situation that requires you to make a decision. A decision that will determine, say, your next 20 years. This was the same situation Motorola faced in the early 1980s.

Motorola was losing market share in its key market segments – semiconductors, car radios, and television. The then CEO, Bob Galvin, called for a meeting to address the lingering issue. During the meeting, many senior executives gave reasons why they felt Motorola wasn’t doing well. As expected, their responses were politically correct but the main issue was still unsolved.

Suddenly, from the back of the room came a lone voice saying ‘our quality stinks!’. This was Art Sundry’s voice, a sales manager at that time. Due to the brevity displayed by Art Sundry, Motorola went on a search for ways to improve its quality.

Bill Smith and Mikel Harry started this search. Their discoveries gave birth to what today we call ‘Six Sigma’.

General Electric (GE), through the leadership of the former CEO Jack Welch, has been at the forefront of quality management. GE saved more than $12 billion five years after they adopted and implemented Six Sigma.

Please, visit our ‘history of Lean Six Sigma’ page to learn more. 

Framework 

Lean
Waste

The goal of Lean is to eliminate waste which in turn improves quality and reduces production time and cost. But ‘waste’ sounds vague, isn’t?

Taiichi Ohno of Toyota introduced a concept to help know what constitute a waste. He called this concept ‘Muda’. Muda is a Japanese word that means ‘wastes’.

Taiichi actually identified seven types of waste. Later, another one was added, making it a total of eight. The eight types of waste are:

Defects

Overproduction

Waiting

Non-utilized talents

Transportation

Inventory

Motion

Extra-processing

Did you find a pattern? I’m sure you did. DOWNTIME is a mnemonic you can use to remember the types of waste.

To know the meaning of each type of waste, please visit our ‘Lean Six Sigma methodology’ page. 

Principles

There are principles that help people to put the Lean framework into practice. These principles are:

Value

Value stream

Flow

Pull

Perfection

To know more about these principles, please visit our ‘Lean Six Sigma methodology’ page.  

Tools and Techniques

Lean tools and techniques help professionals to carry out process improvement tasks and activities. Some of the tools and techniques used in Lean include:

Kanban

VSM (Value stream mapping)

Poka Yoke

Kaizen

Heijunka

Gemba (Go & See)

Just in Time:

Jidoka (Autonomation)

SMED

To know more about these tools and techniques, please visit our ‘Lean Six Sigma methodology’ page. 

Six Sigma 

Principles

There are principles in Six Sigma, just as we have for Lean. However, Six Sigma principles are different from Lean. The Six Sigma principles are:

Be proactive in eliminating waste and continually improve processes.

Prevent defects by reducing or removing variation.

Be flexible, adaptive and thorough

Ensure your processes flow smoothly

Understand how work gets done and identify the root causes of

problems or defects.

Always focus on customer requirement.

Work collaboratively with others. Engage everyone in your team. 

DMAIC methodology

This is an approach that helps to improve an already existing process. DMAIC stands for Define, Measure, Analyze, Improve and Control. 

DMADV methodology

Sometimes people confuse DMAIC with DMADV. DMADV is an approach that is used to design a new process. It is often referred to as DFSS (Design For Six Sigma).

DMADV stands for Define, Measure, Analyze, Design, and Verify.

To know more about DMAIC and DMADV, please visit our ‘Lean Six Sigma methodology’ page. 

Six Sigma tools and techniques

Again, the tools and techniques used in Six Sigma are different from those used in Lean. Some of the tools and techniques used in Six Sigma include:

Ishikawa diagram

Design of Experiment

5 whys

RACI matrix

Pareto chart

Process mapping

To know more about Six Sigma tools and techniques, please visit our ‘Lean Six Sigma methodology’ page.

Lean and Six Sigma are two different process improvement and quality improvement methodologies. Both address two different things. Lean focuses on the elimination of waste, while Six Sigma focuses on the reduction of mistakes or defects. In addition, Lean and Six Sigma started at different times. Also, the principles, tools, and techniques used in both are different.

In conclusion, the next time you are asked; ‘is Lean and Six Sigma the same?’, I am sure you will know what to say. 

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