15 Must-Know Lean Six Sigma Concepts

15 Must-Know Lean Six Sigma Concepts

Lean Six Sigma is a combination of the managerial concepts of Lean and Six Sigma. In the 2000s Lean Six Sigma was first introduced as a concept in the book called “Leaning into Six Sigma: The Path to  Integration of Lean Enterprise and Six Sigma”. Another book titled “Lean Six Sigma: Combining Six  Sigma with Lean Speed” presented the combination of the concepts of Lean and Six Sigma. Both  these books proved to be a guide for organizations to achieve operational excellence.


What is Lean Six Sigma?

Lean Six Sigma is a powerful tool that aims at analyzing processes and removing resources that do not create value to the end customer. It is the combination of two process  improvement methods – Lean and Six Sigma.

Lean – Lean concept was born out of large-scale manufacturing companies, but in the  recent times it has been widely used in all aspects of the business world. Lean is a system  that is focused on delivering maximum value to the customer using minimum resources. A  common misconception is that lean is a cost reduction program, which is not true. It is  about using optimum resources to derive maximum customer value. It aims to identify and  remove seven types of waste that are incurred in a process, which are – waiting, defects,  overproduction, inventory, transportation, motion, and over-processing.

Six Sigma – The concept of Six Sigma originated in the 1980s at Motorola. It is an approach through which organizations improve performance and decrease variation in processes that lead to reduction in defects and improvement in the quality of products and services, profits, and employee morale.


Although various Six Sigma methods are used to solve problems and discover variations, the DMAIC is the standard methodology most practitioners use. The DMAIC has five phases:

Lean and Six Sigma may be different approaches, but when used together it becomes a powerful tool for increasing efficiency – Six Sigma tools can be used to identify process variations and with the help of Lean concepts these variations can be eliminated.

There is a long list of Lean Six Sigma tools that have been developed over the years to tackle quality control and waste issues. Here we have listed 15 essential tools that can be useful under different business conditions.

15 Lean Six Sigma concepts and tools:

1.      The Five Whys

The 5 Whys is a tool used to find out the main cause of problems arising within an organization. Every team or process faces problems in its daily work. The 5 Whys technique can help find the root cause of problems and prevent these problems from relapsing in the future. The basis of this approach is to ask why five times when tackling a problem. The successful implementation of this technique results in making an informed decision because often times the root cause of the initial problem turns out to be completely different from most expectations.

Here is an example of solving a problem using this technique:

Source: Mindtools

2.      Value Stream Mapping

Value stream mapping is used to identify the steps needed to be taken for project completion or  product delivery. It helps team members in understanding every part of the part of the  process/project and checking essential timelines. Since steps in the process are clearly defined, it is easier to perform analysis for improvement.

Source: Wikimedia


3.      Cellular manufacturing

Cellular manufacturing aims at producing a wide variety of products quickly, using as fewer waste as possible. The manufacturing processes are divided into cells which are composed of one or more  different machines to complete a certain task. The product moves from one cell to the next in the process until it is completed. This technique provides operational autonomy, as all the required  manpower and machines are contained within their specific task cell. 

Source: EPA 

4.     SMED

SMED, which stands for Single-Minute Exchange of Dies, is a system for reducing equipment
changeover time by converting as many changeover steps as possible when the equipment is running, and by simplifying and streamlining the remaining steps. With the changeover time reduced, the manufacturing costs will be reduced and there will be smaller lot sizes. Other benefits of this technique are flexibility in meeting customer demand and lower inventory levels.

5.     Five S

5S is a methodology aimed at creating a well-organized workplace that is uncluttered, clean, and safe. This results in increased productivity, both physically and mentally. This process involves 5 concepts beginning with the letter “S” derived from Japanese terms.

a)     Seiri (sort) – Identify unnecessary tools and parts, and get rid of them.

b)     Seiton (set) – Organize and arrange the remaining necessary parts.

c)      Seiso (shine) – Inspect the workspace daily and clean regularly.

d)  Seiketsu (standardize) – Set the standards for the previous steps and record them.

e)     Shitsuske (sustain) – Once the standards are in place, ensure everyone in the organization understands them and follows them.

6.     Kaizen

Kaizen is a Japanese term derived from two words, Kai – change and Zen – good which literally means good change. In other words, improvement. It is the practice of consistently detecting, identifying, and implementing improvements in processes. It encourages everyone in the organization to be involved in the process of executing improvements. With the implementation of Kaizen, there will gradually be a decrease in waste because of the collective knowledge of everyone in the organization working together to handle the smallest inefficiencies.

Kaizen follows the PDCA pattern – Plan, Do, Check, and Act. 

7.      Kanban System

Kanban is a system for implementing a just-in-time inventory control mechanism to ensure cost  reduction. Kanban is a Japanese term, which translates as billboard or signboard. It encourages full  transparency of work and real-time communication of work items, which are presented on a Kanban board for everyone in the team to see the progress of each work item at any time. Work items are  usually categorized into three, with variations depending on the type of work – To Do, Doing (Work-in-progress), and Done..7

Source: Medium

8.     Pareto Chart

Pareto chart is a graphical representation of the differences in groups of data, making identification of the issues arising in the process easier. The x-axis represents the metrics of different business
components such as machine parts or transportation and the y-axis represents defect frequencies and the cumulative percentage. This method is most useful when you want to focus on the most significant problem or cause, in case of multiple problems in a process.

Source: Tallyfy

9.      Takt Time

Takt time refers to the time it takes to produce a finished product in order to satisfy customer demand. It allows optimization of production capacity to meet demand, without having to keep a lot of inventory in reserve.

Takt time is calculated using the below formula:

It can help
maintain a continuous flow of work, and reduce waste and storage costs in the process. Although it is most commonly used in production lines, it can be used for every task in the business world.

10.  Total Productive Maintenance

Total productive maintenance (TPM) is an approach towards effective equipment maintenance, around the idea that everyone in a facility is responsible for everyday maintenance rather than just the maintenance team. It emphasizes on proactive action to achieve operational efficiency of equipment. When all the employees contribute to maintenance, there are fewer breakdowns, no defects or accidents,
and leads to a safer work environment.


11. Poka Yoke/Mistake Proofing

Poka yoke is a Japanese term for mistake proofing. It is a methodology which aims at identifying and eliminating human error by ensuring that the right conditions exist before a step in the process is executed. Poka yoke promotes accountability and prevents defects because of its proactive nature.

One example of Poka yoke is household appliances such as washing machines and microwaves that do not operate unless the doors are closed.

12.      RACI Matrix

RACI matrix is a responsibility assignment chart used to assign roles and responsibilities for every task, milestone, or key decision involved in completing a project. This helps in eliminating confusion. RACI stands for:

a)   Responsible – It defines who is responsible for completing the task.

b) Accountable – It is the person assigning the tasks and checking their progress.

c) Consulted – It refers to the stakeholders who are required to give their input before the work is completed.

d)  Informed – It refers to the stakeholders who need to be notified about the work progress and also when the task is completed.

Example of an RACI chart:

Source: Tallyfy

13.      Heijunka/Leveling the Workload

Heijunka is a Japanese word which means leveling. It is used to minimize the occurrence of overburden and reduce unevenness in the process. This strategy is especially helpful when planning different product mix and in matching unpredictable customer demand, by leveling the volume and product type. It offers the flexibility of producing what the customer wants and when they want it and reduced inventory volume of unsold goods.

14.      FMEA

FMEA stands for Failure Modes and Effects Analysis. It is an approach structured to discover potential failures that is likely to exist in the design of a process or product. It is used to review assemblies and components to identify Failure modes (the ways in which a process can fail) and their Effects (the  ways that these failures can lead to waste or harmful outcomes). FMEA is adopted to improve the quality of the processes by detecting and fixing problems before they can occur. Here is an example of FMEA used in a seat belt installation process:

Source: MoreStream

15.      Cause-and-Effect Analysis

A cause-and-effect analysis is a graphical tool used to capture the possible causes of a problem. It can be used for both analyzing the problem to find the root cause, and to improve the process. This tool is also known as the fishbone diagram because of the shape it takes. The problem that is analyzed is listed at the head of the skeleton, and the diagonal lines around the spine are the factors that may be part of the problem.

An example of Fishbone diagram:

Source: Mindtools

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