Define Lean

Lean Thinking: History and Synergy with Six Sigma

Lean thinking, often referred to simply as “Lean,” is a powerful philosophy and methodology that has revolutionized the world of process improvement and operations management. Originating in manufacturing but now applied across various industries, Lean has a rich history and unique principles that distinguish it from Six Sigma. Here we delve into what Lean is, its historical roots, how it differs from Six Sigma, and how these two methodologies can be used together to achieve exceptional results.

Defining Lean

Lean is a systematic approach to eliminating waste and optimizing processes to create more customer value while using fewer resources. At its core, Lean seeks to improve efficiency, reduce lead times, enhance quality, and increase customer satisfaction. This methodology emphasizes a relentless pursuit of continuous improvement, making it a cornerstone of modern management.

The History of Lean

Lean’s origins can be traced back to post-World War II Japan, particularly the Toyota Motor Corporation. The system developed at Toyota was initially called the Toyota Production System (TPS). Key figures like Taiichi Ohno and Shigeo Shingo played pivotal roles in shaping TPS into what we now know as Lean. The system was designed to minimize waste, increase productivity, and produce high-quality vehicles efficiently.

Over time, Lean principles extended beyond manufacturing and were adopted in various sectors, including healthcare, logistics, and service industries. The term “Lean” was coined in the late 1980s by John Krafcik in his research at the Massachusetts Institute of Technology (MIT), helping to popularize Lean thinking worldwide.

How Lean Differs from Six Sigma

While Lean and Six Sigma share a common goal of process improvement, they differ in their approaches, tools, and focus areas:

  1. Focus on Waste Reduction: Lean places a primary emphasis on identifying and eliminating waste, which it categorizes into seven types (transportation, inventory, motion, waiting, overproduction, overprocessing, and defects). Lean seeks to streamline processes to achieve flow and efficiency.

  2. Customer-Centric: Lean is customer-centric and prioritizes delivering value according to customer needs and preferences. It focuses on creating products or services that customers want, when they want them, and in the desired quantity.

  3. Simplicity: Lean tends to favor simple and visual tools, such as value stream mapping, Kanban, and 5S, to improve processes and enhance communication. It encourages frontline employees to participate in problem-solving actively.

  4. Quick Implementation: Lean initiatives often aim to rapidly implement improvements to address immediate issues and generate quick wins.

In contrast, Six Sigma:

  1. Focus on Variation Reduction: Six Sigma emphasizes reducing process variation and defects to achieve consistent and predictable outcomes. It relies heavily on statistical analysis and tools like DMAIC (Define, Measure, Analyze, Improve, Control) and DMADV (Define, Measure, Analyze, Design, Verify) to identify and address root causes of problems.

  2. Data-Driven: Six Sigma is highly data-driven and employs statistical techniques to measure, analyze, and control processes. It seeks to achieve sigma levels, indicating how far a process deviates from perfection.

  3. Structured Approach: Six Sigma follows a structured, step-by-step methodology that typically requires specialized training for Green and Black Belts.

Using Lean and Six Sigma Together

While Lean and Six Sigma have distinct methodologies, they are not mutually exclusive. In fact, they can complement each other exceptionally well, resulting in a powerful synergy often referred to as Lean Six Sigma (LSS). Here’s how they can be used together:

  1. Lean First, Then Six Sigma: Organizations often initiate process improvement efforts with Lean principles to streamline processes and reduce waste. Once processes are more stable and efficient, they may apply Six Sigma tools to reduce variation and defects further.

  2. Identifying Synergies: Lean can help identify the low-hanging fruit of waste reduction, while Six Sigma can be used for more complex, data-driven projects. Teams can decide which approach to apply based on the nature of the problem.

  3. DMAIC and Lean Tools: The DMAIC methodology of Six Sigma can incorporate Lean tools and principles at various stages. This hybrid approach allows for a structured analysis while leveraging Lean’s simplicity and focus on customer value.

  4. Continuous Improvement Culture: Combining Lean and Six Sigma fosters a culture of continuous improvement, where employees are empowered to identify waste, reduce variation, and innovate. This culture shift can lead to sustainable improvements.

Tools used in Lean

Lean methodology relies on a variety of tools and techniques to identify and eliminate waste while improving process efficiency and quality. Here are five commonly used tools in Lean:

  1. Value Stream Mapping (VSM): Value stream mapping is a visual tool that helps organizations analyze and understand the flow of materials, information, and activities within a process. By mapping the current state and designing a future state, teams can identify areas of waste and develop strategies to improve process flow.

  2. 5S (Sort, Set in order, Shine, Standardize, Sustain): 5S is a systematic approach to workplace organization and cleanliness. It aims to create an organized, efficient, and standardized work environment by sorting and organizing items, maintaining cleanliness, and setting clear standards for maintaining order. The goal is to improve productivity and safety.

  3. Kaizen: Kaizen, which means “continuous improvement” in Japanese, is a philosophy and methodology that encourages small, incremental improvements to processes and systems. It involves a structured approach to identifying areas for improvement, implementing changes, and continuously monitoring and refining processes.

  4. Kanban: Kanban is a visual scheduling system used to manage workflow and control the production or delivery of goods or services. It uses visual signals, often in the form of cards or boards, to signal when and what to produce or deliver. Kanban helps reduce overproduction and inventory while maintaining a smooth flow of work.

  5. Poka-Yoke (Mistake-Proofing): Poka-yoke is a technique used to prevent process mistakes and errors by designing foolproof mechanisms or controls. These mechanisms are designed to make it impossible or highly unlikely for errors to occur. This tool is essential for improving process quality and reducing defects.

These Lean tools, among others, are instrumental in identifying and eliminating waste, optimizing processes, and fostering a culture of continuous improvement within organizations.

Benefits to Shareholders

Shareholders of a company typically embrace the implementation of Lean Six Sigma within the organization due to its proven track record of delivering substantial benefits. Lean Six Sigma translates into improved operational efficiency, reduced costs, enhanced product and service quality, and ultimately, increased profitability. Lean Six Sigma optimizes resource utilization and maximizes shareholder value by eliminating waste, streamlining processes, and reducing defects. Additionally, the methodology’s data-driven approach provides a transparent and accountable framework for decision-making, instilling confidence among shareholders that the organization is actively working to enhance its competitive edge and financial performance. In essence, Lean Six Sigma signifies a commitment to delivering consistent, high-quality results, making it an appealing strategy for shareholders seeking long-term growth and sustainable investment returns.

Benefits to a Company's customers

Implementing Lean Six Sigma is highly beneficial for a company’s customers as it directly translates into a superior experience and value. By eliminating waste, reducing variability, and enhancing efficiency, Lean Six Sigma enables organizations to deliver products or services that are more reliable, consistent, and cost-effective. This means shorter lead times, reduced errors, and improved quality, all leading to increased customer satisfaction. Customers appreciate receiving products or services that meet their expectations consistently, and Lean Six Sigma ensures that organizations can consistently meet or exceed those expectations. Furthermore, the methodology’s customer-centric focus ensures that customer feedback is actively sought and integrated into process improvements, resulting in a continuous cycle of enhancing the customer experience. Implementing Lean Six Sigma benefits a company’s bottom line and ensures that customers receive higher-quality products or services, making it a win-win situation for both the company and its valued customers.

Lean Six Sigma Certification vs. just a Six Sigma Certification

Obtaining a Lean Six Sigma certification instead of solely a Six Sigma certification can offer several advantages and make you a more versatile and effective process improvement professional. Here are some reasons why someone might choose to get a Lean Six Sigma certification:

  1. Comprehensive Skill Set: Lean Six Sigma combines the principles of Lean and Six Sigma, giving you a broader skill set. You’ll not only learn to reduce process variation (Six Sigma) but also eliminate waste, streamline processes, and enhance efficiency (Lean). This comprehensive approach allows you to address a wider range of operational issues.

  2. Adaptability: Lean Six Sigma equips you to work in a variety of industries and settings. Lean principles are applicable in manufacturing, healthcare, services, and more. This adaptability enhances your career prospects and makes you a valuable asset in different organizational contexts.

  3. Holistic Problem-Solving: With a Lean Six Sigma certification, you’ll have a holistic problem-solving toolkit. You can tackle complex issues involving variability and inefficiency, allowing you to address root causes more effectively and achieve sustainable improvements.

  4. Increased Efficiency: Lean principles focus on streamlining processes and eliminating waste, leading to increased operational efficiency. By understanding both Lean and Six Sigma, you can identify opportunities for efficiency gains that may be missed with a Six Sigma-only approach.

  5. Customer-Centric Approach: Lean Six Sigma emphasizes the importance of delivering value to customers. This customer-centric perspective ensures that process improvements align with customer needs and expectations, resulting in higher customer satisfaction and loyalty.

  6. Better Project Selection: Lean Six Sigma professionals can select projects with a more comprehensive view of potential improvements. This helps prioritize projects that reduce defects and optimize processes for greater efficiency and customer value.

  7. Improved Collaboration: Lean and Six Sigma often require collaboration between teams and departments. A Lean Six Sigma certification prepares you to bridge gaps and facilitate cooperation, making it easier to implement cross-functional improvements.

  8. Lean Tools: Lean Six Sigma incorporates a range of Lean tools like value stream mapping, 5S, and Kaizen events. These tools enhance your problem-solving capabilities and offer additional methods for process optimization.

  9. Competitive Advantage: In a competitive job market, having both Lean and Six Sigma skills sets you apart from candidates with only one of these certifications. Employers often seek professionals who can contribute to a wide array of process improvement initiatives.

  10. Organizational Impact: With a Lean Six Sigma certification, you can drive more significant and holistic improvements within your organization. Your ability to deliver value, reduce waste, and optimize processes aligns with the strategic goals of many companies.

Obtaining a Lean Six Sigma certification offers a broader and more versatile skill set encompassing both Lean and Six Sigma principles. This can enhance your career prospects, enable you to address a wider range of process improvement challenges, and make you a valuable asset in various industries and organizational contexts.


Lean, with its roots in Toyota’s production system, is a philosophy that emphasizes waste reduction, customer focus, and simplicity. While different from Six Sigma, which centers on variation reduction through data-driven methods, Lean and Six Sigma can work together seamlessly to drive efficiency and quality improvements. By using the strengths of both methodologies, organizations can achieve remarkable results and develop a culture of continuous improvement that benefits customers and stakeholders alike.

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