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What is Lean Six Sigma?

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Lean Six Sigma is a comprehensive methodology that aims to improve business efficiency and effectiveness by minimizing waste and variation in processes. It combines two prominent business process improvement strategies: Lean and Six Sigma.

The Components of Lean Six Sigma: Lean and Six Sigma


The Lean methodology, rooted in the Toyota Production System, focuses on eliminating waste from business processes to enhance efficiency and value. Waste refers to any activity that doesn’t add value from the customer’s perspective. It includes overproduction, waiting, transport, over-processing, inventory, motion, and defects (often remembered using the acronym ‘DOTWIMP’).

Six Sigma

Six Sigma, on the other hand, originated from Motorola’s quality improvement method and seeks to reduce variability in processes. Variability refers to deviations from the standard process, leading to quality issues and inefficiencies. The Six Sigma method uses statistical techniques to measure and analyze process variability, with the goal of reducing defects to a rate of 3.4 per million opportunities.

The Combination of Lean and Six Sigma

Lean Six Sigma synergistically combines these two methods. Lean’s focus on reducing waste helps to streamline operations and improve flow, while Six Sigma’s emphasis on reducing variation ensures consistent, high-quality output.

The Historical Roots of Lean Six Sigma

The historical roots of Lean Six Sigma can be traced back to the Toyota Production System for Lean and Motorola’s quality improvement method for Six Sigma.

The Toyota Production System, which forms the basis for Lean, was developed between 1948 and 1975 by key personnel at Toyota. The focus was to meet customer demand efficiently through the elimination of waste and continuous improvement.

Six Sigma was developed by Motorola in 1986 as a data-driven approach to eliminate defects and improve processes. The goal was to identify and remove the causes of defects and minimize variability in manufacturing and business processes.

The idea to combine Lean and Six Sigma methodologies into one integrated approach came later, as businesses recognized the complementary nature of the two strategies. Today, Lean Six Sigma is widely adopted across various industries, not just limited to manufacturing, including healthcare, finance, IT, and more. The methodology has been instrumental in helping organizations achieve process excellence and operational efficiency.

Core Concepts and Principles of Lean Six Sigma

Understanding the core concepts and principles of Lean Six Sigma is vital to successfully apply the methodology in any organization. This combination of Lean and Six Sigma methodologies aims to remove waste and reduce variation in business processes, enhancing efficiency and quality.

Lean Principles

The principles of Lean are centered on waste elimination, process flow improvement, and value delivery from the customer’s perspective. Lean principles are as follows:

  1. Identify Value: Everything begins with understanding what the customer values in the product or service you’re offering. This value is the driving force behind the product or service.
  2. Map the Value Stream: Once value is identified, you map out every step of your product or service’s lifecycle, from beginning to end, highlighting where value is created.
  3. Create Flow: After the value stream is identified, the goal is to ensure that these value-adding steps flow smoothly without interruption or delay.
  4. Establish Pull: This principle means that products or services are produced to meet actual customer demand, not anticipated or forecasted demand.
  5. Pursue Perfection: Lean is about continuous improvement. As waste is removed and processes become more lean, the organization continues to look for ways to make processes more efficient and effective.

Six Sigma Principles

The principles of Six Sigma focus on eliminating process variability, improving quality, and enabling data-driven decision making. Here are the Six Sigma principles:

  1. Focus on the Customer: Like Lean, Six Sigma begins with the customer, focusing on delivering quality as perceived by the customer.
  2. Use Data and Measurement: Decisions should be data-driven. This involves measuring current performance and using statistical analysis to identify root causes of problems.
  3. Focus on Processes: To improve quality, Six Sigma focuses on improving processes rather than individual outcomes.
  4. Be Proactive: Six Sigma encourages proactive management and the prevention of defects before they occur.
  5. Collaboration: Six Sigma projects are often carried out by cross-functional teams, fostering collaboration, and shared ownership of results.

Integration of Lean and Six Sigma

When integrated, Lean and Six Sigma provide a comprehensive approach for operational excellence. The two methodologies complement each other: while Lean focuses on speed and efficiency by removing waste and improving process flow, Six Sigma adds the dimension of quality and precision by reducing process variation. Together, they provide a robust framework for improving efficiency, effectiveness, and customer satisfaction.

The Five Phases of Lean Six Sigma: DMAIC

DMAIC, an acronym for Define, Measure, Analyze, Improve, and Control, is a data-driven quality strategy used to improve processes. It’s the core tool used to drive Six Sigma projects, but it can also be implemented as a standalone quality improvement procedure or as part of other process improvement initiatives such as Lean.


In the Define phase, the team identifies the problem, project goals, and customer (internal and external) requirements. The objective of this stage is to clearly articulate the business problem, goal, potential resources, project scope, and high-level project timeline. These elements are often captured within a project charter.


During the Measure phase, the team identifies the key performance indicators (KPIs) relevant to the business problem, then collects data to determine the baseline performance. The focus is to gain a more detailed understanding of the problem and process. Tools used during this stage may include data collection tools, statistical analysis tools, process mapping, and others.


The Analyze phase uses statistical analysis and hypothesis testing to model how processes may be improved and to identify the root cause of the problem. At this stage, the team will further refine their understanding of the relationships between variables and establish the statistical relationship and validity.


During the Improve phase, the team generates, selects, and implements solutions that address the root cause in order to fix and prevent process issues. This involves piloting changes, and if successful, implementing them on a wider scale. The team should monitor the improvements to ensure they are effective.


The Control phase ensures that the improvements made are sustained over time. This is achieved by setting up control plans, having response plans ready, and continuously monitoring the process. The results are documented, and team members are recognized for their contributions. After this, the team hands the process back to the process owner with a Control Plan to ensure the new process is followed.

Together, the DMAIC phases provide a structured approach to problem-solving and process improvement, ensuring that the root cause is identified and properly addressed, leading to sustained improvement.

Roles and Responsibilities in Lean Six Sigma

Lean Six Sigma incorporates a hierarchical structure of roles and responsibilities, usually denoted by different belt colors, akin to martial arts. The level of responsibility and expertise increases with each belt color, ranging from Yellow to Master Black Belt. Let’s explore each role in more detail.

Yellow Belt

Yellow Belts are typically employees who are new to Lean Six Sigma. They understand the basic principles and can contribute to projects by supporting process improvement teams. Yellow Belts often participate part-time in Lean Six Sigma projects and have a basic understanding of the tools and techniques used.

Green Belt

Green Belts typically spend a portion of their time on process improvement teams. They analyze and solve quality problems, usually under the guidance or coaching of a Black Belt. Green Belts are proficient in the use of Lean Six Sigma tools and techniques and can lead small-scale improvement projects within their functional area.

Black Belt

Black Belts are experienced and highly trained Lean Six Sigma professionals. They lead project teams and are responsible for implementing process improvements across the organization. A Black Belt should demonstrate team leadership, understand team dynamics, and assign team member roles and responsibilities for project success.

Master Black Belt

Master Black Belts have achieved the highest level of technical and organizational proficiency. Their role is typically more strategic, and they are responsible for the development of project charters and strategic deployment. They also provide training, coaching, and mentoring to Green and Black Belts.


Champions are usually members of the management team who understand Lean Six Sigma and are committed to its success. They help to select the right projects, identify Black and Green Belt candidates, mentor and coach Black and Green Belts, and remove any roadblocks that project teams may encounter.

These roles help to distribute the responsibilities and tasks of Lean Six Sigma projects across a team, ensuring efficient use of resources and promoting a culture of continuous improvement within the organization. The effectiveness of Lean Six Sigma relies heavily on the participation and commitment of these role holders.

Benefits and Advantages of Implementing Lean Six Sigma

The implementation of Lean Six Sigma principles can offer a host of benefits to businesses, regardless of their size or the industry in which they operate. From enhancing efficiency to promoting a culture of continuous improvement, Lean Six Sigma has the potential to drive significant improvements in a company’s operations and outcomes.

Improved Operational Efficiency

By focusing on eliminating waste and reducing variability in processes, Lean Six Sigma helps to streamline operations and make them more efficient. This can lead to significant time and cost savings, enabling the company to deliver products and services more quickly and at a lower cost.

Enhanced Customer Satisfaction

Lean Six Sigma’s emphasis on delivering value from the customer’s perspective leads to improved product quality and service delivery. This can significantly enhance customer satisfaction, leading to increased customer loyalty and a stronger competitive position in the market.

Cost Reduction

By reducing waste and process variability, Lean Six Sigma helps to cut costs. This includes reducing defects, overproduction, waiting times, non-utilized talent, transportation, inventory, motion, and extra-processing. This cost reduction can lead to increased profits and better financial performance.

Employee Engagement and Empowerment

Lean Six Sigma fosters a culture of continuous improvement and encourages employees to participate in problem-solving and process improvement. This not only empowers employees but also enhances their engagement, leading to increased productivity and innovation.

Risk Management

By applying Six Sigma principles, businesses can anticipate potential problems before they occur and implement preventive measures. This proactive approach to risk management can lead to fewer crises, more predictable processes, and improved organizational resilience.

In summary, the benefits of implementing Lean Six Sigma are manifold, leading to operational improvements, increased customer satisfaction, cost reduction, and enhanced employee engagement. By promoting a culture of continuous improvement and excellence, Lean Six Sigma can be a powerful tool for business transformation.

Real-world Applications and Case Studies of Lean Six Sigma

Lean Six Sigma principles are not limited to specific industries or sectors; they are universally applicable and have been successfully implemented across a wide range of contexts. From manufacturing and healthcare to service industries, the Lean Six Sigma methodology has helped many businesses to enhance their operational efficiency and overall performance.

Manufacturing: Streamlining Production and Reducing Defects

A prominent example of Lean Six Sigma application in manufacturing is at General Electric (GE). The company adopted the Six Sigma methodology in the mid-1990s and has since realized billions in savings. Through the systematic application of Lean Six Sigma principles, GE was able to significantly reduce defects in their manufacturing processes, leading to improved product quality and reduced costs.

Healthcare: Minimizing Errors and Improving Patient Care

In healthcare, Lean Six Sigma has been used to improve patient care by reducing errors and increasing efficiency. For example, CHOP in the United States applied Lean Six Sigma principles to streamline its medication delivery process. By mapping out the entire process and identifying sources of waste and variability, the hospital was able to reduce medication delivery times, leading to improved patient satisfaction and safety.

Service Industry: Optimizing Customer Service and Operational Efficiency

In the service industry, the Bank of America serves as a case study of successful Lean Six Sigma implementation. By applying Lean Six Sigma principles, the bank was able to streamline its processes and eliminate non-value-adding activities, leading to improved operational efficiency and customer service. As a result, the Bank of America reported significant cost savings and improved customer satisfaction scores.

These case studies demonstrate the transformative impact of Lean Six Sigma. When correctly implemented, this methodology can significantly improve operational efficiency, reduce costs, enhance customer satisfaction, and foster a culture of continuous improvement. Regardless of the industry or sector, Lean Six Sigma offers a powerful approach for businesses striving for excellence and seeking to gain a competitive edge in today’s challenging business landscape.

Lean Six Sigma Training and Certification

Proper training and certification are essential for anyone seeking to fully understand and apply the principles and tools of Lean Six Sigma. A comprehensive training program typically includes a combination of coursework, examinations, and practical projects to demonstrate applied knowledge.


The coursework in a Lean Six Sigma training program typically covers a wide range of topics, from the foundational principles and methodologies of Lean and Six Sigma to the specific tools and techniques used in each phase of the DMAIC cycle. Coursework often includes both theoretical learning and practical exercises to help students apply what they’ve learned.


Following the coursework, students typically must pass an examination to demonstrate their understanding of Lean Six Sigma principles and methodologies. These exams often test a wide range of knowledge, including the understanding of the DMAIC cycle, proficiency in statistical analysis, and the ability to apply Lean Six Sigma tools to real-world scenarios.

Practical Projects

In addition to coursework and exams, Lean Six Sigma certification often requires the completion of a practical project. These projects give students the opportunity to apply their knowledge and skills in a real-world context. Depending on the level of certification, the project may involve leading a team to improve a process within an organization.

Certification Providers

Numerous organizations offer Lean Six Sigma certification, ranging from universities and colleges to private companies. When choosing a certification provider, it’s important to consider factors such as the program’s reputation, the comprehensiveness of the curriculum, the credentials of the instructors, and the support provided for practical projects.

In conclusion, Lean Six Sigma training and certification provide a structured and comprehensive way to gain a deep understanding of this powerful methodology. By combining coursework, examinations, and practical projects, these programs equip individuals with the knowledge and skills needed to drive significant improvements in their organizations.


In conclusion, Lean Six Sigma offers an effective framework for continuous improvement and operational excellence. Its value has been demonstrated across industries, and despite its challenges, its benefits often outweigh the difficulties. Organizations seeking to enhance efficiency, effectiveness, and customer satisfaction should consider the potential of Lean Six Sigma. The drive towards continuous improvement is more than a methodology—it’s a mindset that paves the way for sustainable success.

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