What is Lean Six Sigma ?

Lean Six Sigma is the most practiced Management approach in today’s time. A good number of organizations have adopted Lean Six Sigma as a way of working and many other are following. It’s so, because Lean Six Sigma gives a competitive edge to your organization and the results are visible in a short span of time. Some of the organizations that claim to follow Six Sigma are :

Six Sigma Companies 

What is Six Sigma ?

  • A performance goal, representing 3.4 defects for every million opportunities
  • A series of tools and methods used to improve or design products, processes, and/or services.
  • A statistical measure indicating the number of standard deviations within customer expectations.
  • A disciplined, fact-based approach to managing a business and its processes.
  • A means to promote greater awareness of customer needs, performance measurement, and business improvement.

What is Sigma ?

  • Sigma is a Greek letter representing the standard deviation of a population of data. It’s a measure of variation.
  • Variation means that a process does not produce the same result (the “Y”)   every time.
  • Some variation will exist in all processes.
  • Variation directly affects customer experiences.
  • Customers don’t feel averages
  • Managing by the average doesn’t tell the whole story. The average and the variation together show what’s happening.

Example :

  • Customers want their pizza delivered fast! A popular brand of Pizza claims that there average delivery time is 23 min against the target of 30 min. The performance is great , isn’t it ? The customers must be happy , right ? Look the graph below:

The average delivery time is 23 min, but look at the variation, there are many deliveries beyond 30 min, certainly those customers wont be happy who get delivery after thirty min. So, what to do ? Reduce Variation to Improve Performance .

This is what Six Sigma does. It has tools that you can use to reduce variation. You can notice that the number of deliveries that are going beyond 30 min has significantly reduced.

If 30 min is our goal, then everything that is delivered after 30 min is not acceptable (Defect, in the language of Six Sigma).

Six Sigma also empowers you to predict how many defects will be produced in a process. This is found by mapping Sigma Level of your process and then finding DPMO (Defects per Million Opportunities)

Here is the Sigma Scale :-

Thus, a process that is at 6 Sigma level will produce no more than 3.4 defects per million opportunities. What does this imply? This implies a minuscule level of rejection/defect.

Observe the table below to evaluate the difference between a 3 sigma and a 6 sigma process

Now you can see, Why this philosophy is called Six Sigma. At a sigma level of Six, the Quality that you delivery is very high as the no. of defects are very less.

Six Sigma follows a very structured approach of Problem Solving / Process Improvement – DMAIC.

To know more about DMAIC , please  read the following blog:

Looking for Effective Process Management? Follow these 5 Six Sigma principles

Six Sigma has three unique features

1. It has a ROI (Return on Investment) based approach

Six Sigma projects begin with an ROI estimate. It’s a very business oriented approach. ROI is estimated when a Project Charter is created in the Define Phase. Sometimes, we do take up softer aspects of business like Improving customer Satisfaction or employee morale, but Six Sigma Project taken at Black-Belt hit either the bottom line or improve customer satisfaction significantly.

2. It certifies people for their competency

Six Sigma approach is heavily people driven. It encourages organizations to train it’s people in the disciplined approach of Six Sigma. Therefore, we have Certified Yellow Belt , Green Belt and Black Belts.

To know more about the Six Sigma Certifications, please go through the following blog :

Beginner’s guide to six sigma Certification

3. It’s a disciplined approach with a set of tools to use

Six Sigma uses DMAIC approach for problem-Solving / executing projects.

It has a set pattern in which the project is executed – Define the problem, Measure the current State and extent of the problem, analyze root causes, propose and implement Improvement actions and finally put controls in place, so that the improvements remain intact.

To know more about Six Sigma, take this short course :


Now, let move on to understand Lean.

What is Lean ?

Lean originated in the Japaneses automotive Industry when Japan was trying to rebuild it’s economy after the 2nd World War. It was in dire need of producing good Quality Products at a competitive price. Some of the Lean concepts actually emerged at Toyota and the practices followed at Toyota , called the Toyota Production System eventually came to known as Lean .Lean brings you Quality with speed.

Lean is based on 5 Key Principles:

  1. Identify customer and specify Value
  2. Identify and map Value Stream
  3. Create flow by eliminating waste
  4. Respond to customer Pull
  5. Pursue Perfection

To read more about Lean Principles, here is a blog for you:

5 Lean Principles Every Engineer Should Know

Lean Temple / Lean Tools:

Lean Improvements in the organization first demand that there should be Stability in the organization.In the simplest sense this implies general predictability and consistent availability in terms of manpower, machines, materials, and methods — the 4Ms

Before any organization, embarks on lean Journey, these are the Questions that it needs to ask itself:

1.Do you have enough machine uptime to produce customer demand?

2. Do you have enough material on hand every day to meet your production needs?

3.Do you have enough trained employees available to handle the current processes?

4.Do you have work methods, such as basic work instructions, defined or standards in place?

Then comes 5 S and Kaizen.


The 5S‘s are simple but effective methods to organize the workplace.

The methodology does, however, go beyond this simple concept, and is concerned with making orderly and standardized operations the norm, rather than the exception.


Kaizen means improvement.

Improvements without spending much money, involving everyone from managers to employees and using much common sense.The aspect of Kaizen is that it is ongoing and never-ending improvement process.


Hejunka implies Leveling the type and quantity of production over a fixed period of time. The synonym for Hejunka are Level Production or Production Smoothing

It Enables production to efficiently meet customer demands

This Results in minimum inventories, capital costs, manpower, and production lead time through the whole value stream.

Standard Work

Standard work represents the best, safest, and easiest way to do a job

It is the most effective combination of manpower, materials and machinery to complete a specific task.

Standard work results in a formally defined and documented process to produce or perform a task at a specified pace.


The term jidoka used in the TPS (Toyota Production System) can be defined as “automation with a human touch.” The word jidoka traces its roots to the invention of the automatic loom by Sakichi Toyoda, Founder of the Toyota Group. The automatic loom is a machine that spins thread for cloth and weaves textiles automatically.

To learn about the Lean tools in detail, take the orientation course on Lean tools and concepts, for free: http://www.sigmasavvy.com/lean-essentials/http://www.sigmasavvy.com/lean-essentials/

How Six Sigma & Lean work together?

Whereas Six Sigma is most closely associated with defects and quality, Lean is linked to speed, efficiency, and waste. Lean provides tools to reduce lead-time of any process and eliminate non-value add cost. Six Sigma does not contain any tools to control lead time (e.g., pull systems), or tools specific to the reduction of lead time (e.g., setup reduction). Since companies must become more responsive to changing customer needs, faster lead times are essential in all endeavors. Lean is an important complement to Six Sigma and fits well within the Six Sigma DMAIC process. Additionally, the Lean approach is a great method that can be used to accelerate the rate of improvements.

You need to improve quality so you can achieve maximum speed, and you need to do the things that allow maximum speed in order to reach the highest sigma levels of quality. In other words, you need both Lean (speed) and Six Sigma (quality) principles and tools to drive improvements in ROI and achieve the best competitive position.

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