Lean Six Sigma methodology

Lean Six Sigma methodology

Before we go on to explain Lean Six Sigma methodology, let’s look at the meaning of methodology. A methodology is a set of principles, practices, and theories that a given profession uses. It provides the basis for understanding which method or set of methods to apply in a particular situation. Lean Six Sigma is all about quality. Quality management is the very core of Lean Six Sigma. With this in mind, Lean Six Sigma methodology refers to the methodology used in the quality management profession.

Lean Six Sigma is a combination of two concepts – Lean and Six Sigma. Therefore, the combination of Lean and Six Sigma methodologies gives Lean Six Sigma methodology. We will now look at each methodology separately.

Table of Contents

What is Lean?

Lean is a systematic method or approach for eliminating waste. Waste is anything that does not add value to your product or service. You may want to ask, ‘what is value?’ Simply put, ‘value’ is anything a customer is willing to pay for. In other words, anything that exceeds just the right amount of equipment, materials, parts, space etc. is considered a waste.

Eliminating waste

Elimination of waste improves quality, reduces production time and cost. Although eliminating waste seems like a simple thing to do, it is actually not that easy. One of the tenets of ‘Lean Thinking’ is to identify activities or steps that constitute ‘waste’. For this reason, Taiichi Ohno of Toyota introduced a concept known as ‘Muda’. Muda is the Japanese word for wastes. He originally identified seven types of waste or muda. Later, an eight waste was added (a good mnemonic to use here is (DOWNTIME). Below shows the waste and their description:

Defects: This refers to the efforts put in a rework by checking and fixing errors or mistakes. Also, it means having to discard or rework a product as a result of defective components. All these results in delays and additional cost.

Over-production: This waste arises when more than the required product is produced.

Waiting: This refers to the time spent when a product is idle. In other words, it is the time spent when a product is not being worked on or transported.

Non-utilized talents: This waste arises when employees do not use their skills optimally due to restrictions. Essentially, it means not leveraging people’s talents and skills.

Transportation: This occurs when products, equipment, material, etc. are moved from one place to another without any value addition. Hence, transportation exposes inputs to damage, loss, theft, delay, etc.

Inventory: This waste arises due to the unnecessary storage of material or product.  In other words, the longer a product stays, the more the waste. A smooth, continuous flow of work reduces the amount of excess inventory.

Motion: This refers to the damage to equipment, wear and tear, unnecessary movement by workers, injuries or fatigues.

Extra-processing: This occurs when more than the required processes and steps are carried out. These extra processes do not add value to the product or service. Also, it involves the use of complex, expensive or high-value materials beyond what the customer requires.

Lean Principles

Having looked at the meaning of ‘Lean’ and ‘waste’, let’s now discuss the principles that will help eliminate waste.

The five principles of Lean are:

Value: Firstly, define what is of value to the customer. You have to decide what the customer is willing to pay for. In other words, find out what the customer needs.

Value Stream: Secondly, identify all steps and processes that are needed to take the product from start to finish. Here, the goal is to identify every step or activity that does not add value and then eliminate them.

Flow: After removing waste from the value stream, the next thing to do is to ensure a constant flow of value-creating steps. In other words, there shouldn’t be any interruptions or delays.

Pull: As a result of constant flow, the time it takes for products to reach the market can improve significantly. Therefore, it becomes easy to deliver products ‘Just in Time’ (JIT). With this approach, customers can ‘pull’ products from you anytime.

Perfection: Finally, you have to continuously improve the process. You must put in considerable time and effort in improving your existing processes to meet customers ever-changing needs.

Lean Tools and Techniques

Professionals need tools and techniques to carry out their day-to-day activities. Similarly, Lean professionals need tools to help them eliminate waste. Now, let’s look at some of the tools and techniques they use.

Kanban: This is a visual representation that helps manage inventory or set of activities. In other words, Kanban boards show at a glance the level of backlogs.

Just in Time: This is a ‘pull’ approach whereby customers demand are met on time.

Jidoka (Autonomation): This automation stops the production line if a defect or error occurs.

Kaizen: It’s an approach whereby small teams meet on a regular basis to discuss process improvement issues.

Heijunka: The aim here is to evenly distribute workload thereby balancing production lines.

Gemba (Go & See): As the name suggests, it means to go to the actual place of work. The purpose of Gemba is to observe a process, how it is executed and then make recommendations for improvement.

SMED (Single Minute Exchange of Dies): This provides an efficient and rapid way of reducing the time it takes to complete equipment changeovers.

VSM (Value stream mapping): As discussed earlier, VSM helps identifies process wastes with the goal of eliminating them.

Poka-Yoke: This is a mechanism in a process that helps an equipment operator to avoid mistakes.

What is Six Sigma?

Six Sigma is a data-driven approach that focuses on removing defects in processes. It enables organizations to streamline activities, improve quality and eliminate mistakes or defects.

Six Sigma principles

The core Six Sigma principles are:

  • Always focus on customer requirement.
  • Understand how work gets done and identify the root causes of problems or defects.
  • Ensure your processes flow smoothly
  • Be proactive in eliminating waste and continually improve processes.
  • Prevent defects by reducing or removing variation.
  • Work collaboratively with others. Engage everyone in your team.
  • Be flexible, adaptive and thorough.

Six Sigma DMAIC methodology

The Six Sigma DMAIC methodology is an approach that is used to improve an existing process. It is an acronym that stands for:

Define: To clearly state the business problem, the objective of the project, improvement activity, and the desired outcome.

Measure: To objectively establish current starting point as the basis for improvement.

Analyze: To identify, validate and select the root cause of issues or problem.

Improve: To identify, test and implement a solution to the problem.

Control: To sustain the gains, monitor the improvements to ensure continued and sustainable success.

Six Sigma DMADV methodology

The Six Sigma DMADV methodology is an approach that is used to design a new process. It is also commonly called DFSS (Design For Six Sigma). DMADV is an acronym that stands for:

Define: To clearly define the process, desired outcome, and objective.

Measure: To identify and measure features of the product that are critical to quality.

Analyze: To analyze data, identify causes of defects and select the best course of action

Design: To identify, test and implement a design solution that will eliminate the cause of errors or defects.

Verify: To verify the selected design by carrying out a pilot-test and then implement and monitor the new process.

Six Sigma tools and techniques

The following are some of the Six Sigma tools and techniques:

Ishikawa diagram: It is also called cause-and-effect diagram. It identifies many possible causes of a problem

5 whys: This is an iterative technique whereby ‘5 whys’ are asked to unravel the cause-and-effect relationship of a problem.

Pareto chart: This is a graphical chart that summarizes and displays data.

Process mapping: It is the act of creating a workflow diagram in order to understand how processes work.

RACI matrix: RACI is an acronym that means Responsible, Accountable, Consult and Inform. It helps to define and document project roles and responsibilities.

Brainstorming: This is a technique where a group of people meets to generate new ideas and solutions around a problem.

Kanban: This is a visual representation that helps manage inventory or set of activities. Kanban boards show at a glance the level of backlogs.

Design of Experiment: This is a method to determine cause-and-effect relationships. This helps to manage inputs in order to optimize the output.

How to get certified

Getting certified requires that you attend training and then sit the IASSC exam. Harrybaker Training Institute is accredited by IASSC to conduct Lean Six Sigma training and exam.

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


Recertification is required for the three different belts. From the day you are certified, IASSC grants you a ‘current status’. The current status shows that your certification is active. Within three years of being awarded the IASSC certification, you will have to take a recertification exam. If you do not take the recertification exam, IASSC will grant you an ‘elapsed status’. Therefore, to have an ‘active status’, you need to take the recertification exam before the end of the three years or no longer than 90 days after ‘elapsed status; has been granted’.

Are you considering Lean Six Sigma?

At Harrybaker we’re determined to ensure learners pass the Lean Six Sigma exam at the first sitting. My only question is, will it be you?

Please complete the form below to submit an enquiry