What Is Lean Six Sigma?

Better understand the power of Lean Six Sigma, a comprehensive project management methodology popularized by Toyota and Motorola that's now integrated across a range of industries.

June 03, 2025 | By GTPE Communications
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The ever-complicated business landscape relies on structured processes that increase   critical operations efficiency. These activities allow organizations to make clear progress toward ambitious objectives while navigating complex situations and seizing opportunities. However, even the most well-designed processes are prone to challenges, including intense competition within a global market.  

Therein lies the value of a comprehensive methodology known as Lean Six Sigma (LSS). This powerhouse approach blends Lean’s well-established, efficiency-driven mindset with Six Sigma’s precise, innovative problem-solving strategies. 

So, what is Lean Six Sigma? This dynamic framework centers on two distinct yet complementary methodologies to address a variety of challenges that organizations frequently face as they navigate the fine line between driving efficient operations and maintaining optimal outcomes. 

Evolution of Lean Six Sigma 

The principles that underscore Lean Six Sigma were largely formalized by innovative engineers but rose to prominence as they were successfully applied by major corporations such as Toyota and Motorola. Nowadays, they are frequently integrated to optimize processes across a range of industries. 

What Is Lean? 

The Lean methodology focuses on optimizing workflows and reducing waste. It offers a blueprint for limiting these non-value-added activities whenever possible. 

This transformative methodology is often attributed to engineer Taiichi Ohno and the Toyota Production System. This breakthrough involved the concept of kaizen (translating in English to "for the better") to reveal how all employees and stakeholders can lean into efficiency by finding small yet continuous opportunities for improvement. 

What Is Six Sigma? 

Dedicated to process improvement, Six Sigma represents a set of techniques designed to eliminate defects and achieve near-perfect quality. This data-driven process brings a systematic approach to identifying flaws, along with actionable strategies for eliminating these concerns. 

Engineer Walter Shewhart formed the statistical basis for Six Sigma and has therefore been referred to as the “Father of Quality Control.” Engineer Bill Smith brought this concept into the mainstream by successfully introducing it at Motorola during the 1980s, demonstrating how Shewhart's concepts could limit process variations. Then, General Electric CEO Jack Welch also advocated passionately for the adoption of Six Sigma strategies. 

Combining Lean and Six Sigma into Lean Six Sigma 

The fusion of Lean principles and the Six Sigma methodology occurred during the 1990s, revealing that it was possible to integrate these previously distinct methodologies. Advocates recognized that this could produce a unique blend of waste reduction and data-driven optimizations. Today, LSS is a hallmark of efficiency innovation that continues to evolve in response to rapid technological advancements. 

Who Uses Lean Six Sigma? 

Relevant across many fields, Lean Six Sigma is uniquely versatile. Its problem-solving tools and techniques are inherently adaptable. Priorities such as process improvements and data-driven decision-making are applicable within a wide range of sectors and initiatives. The following industries are a few that have integrated LSS methodologies: 

  • Manufacturing  
  • Supply chain  
  • Engineering  
  • Healthcare  
  • Sustainable initiatives  

Belt Levels 

Lean Six Sigma uses its own system of belt colors to signify skill development and advanced knowledge acquisition. The levels resemble the belts used in martial arts but are tailored to reflect the unique skills required for effective LSS implementation. These belts may also align with the amount of authority or autonomy granted to various professionals. Common belt levels include: 

  • Lean Six Sigma White Belt Certification – The White Belt is the entry-level certification in Lean Six Sigma. It introduces fundamental concepts like waste reduction and process improvement. This is ideal for individuals who want a basic understanding of Lean Six Sigma or plan to support larger improvement projects. While foundational, it’s typically a stepping stone toward more advanced belts. 
  • Lean Six Sigma Yellow Belt Certification – The Yellow Belt goes deeper into Lean Six Sigma tools and techniques. It’s suitable for professionals who want to participate in projects more actively. Yellow Belts learn about value stream mapping, root cause analysis, and how to support Green and Black Belt projects through data collection and team coordination.  
  • Lean Six Sigma Green Belt Certification – The Green Belt represents a significant advancement. It certifies that a professional understands and can apply the full DMAIC model (Define, Measure, Analyze, Improve, Control). Green Belts lead smaller projects or assist Black Belts in larger initiatives, using tools like process mapping, statistical analysis, and control charts. 
  • Lean Six Sigma Black Belt Certification – The Black Belt designation demonstrates a high level of expertise in Lean Six Sigma methodology. Professionals at this level are capable of leading complex projects, training team members at lower belt levels, and managing full DMAIC implementations. It’s an excellent option for those pursuing leadership or consulting roles in process improvement. 
  • Lean Six Sigma Master Black Belt Certification – The Master Black Belt is the highest level of Lean Six Sigma certification. It signifies expert-level knowledge of statistical tools, change management, and leadership strategies. Master Black Belts often mentor Green and Black Belts, lead organizational change, and align Lean Six Sigma efforts with strategic business goals. 

The Benefits of Lean Six Sigma 

LSS can help leaders pursue a variety of goals, making it a go-to methodology in dynamic fields that call for innovative solutions. Below are some of the most cited benefits: 

  • Improved quality  
  • Waste reduction  
  • Reduced costs  
  • Data-driven decisions  
  • Employee engagement  
  • Increased revenue  

How to Use Lean Six Sigma 

Lean Six Sigma draws on a five-phase strategy known as DMAIC to optimize critical business designs and processes. This data-driven improvement cycle is navigated sequentially, with each phase fully executed before moving on. These phases build upon one another to deliver continuous improvements. Along the way, teams can leverage various purpose-driven tools and technologies to elevate each phase.  

Define 

One of the core tenets of Lean Six Sigma involves identifying and solving the right problems. This means focusing on concerns that have a documented impact on performance or efficiency. Project statements guide this process. These should feature clear and concise descriptions of identified problems. 

Also crucial is the project charter, which provides a  framework to guide the remainder of the project. This should outline the objectives, scope, and timeline for the project, along with available resources. Aided by project statements and the project charter, the ‘define’ phase aims to reveal the gap between how processes currently function and how these will function following the successful implementation of the full DMAIC model. 

Measure 

Centered on data collection, the ‘measure’ phase aims to establish clear baselines, which can later be compared to performance metrics. This phase leans heavily into a tool known as the process map that provides a step-by-step overview of relationships between inputs, actions, and outputs. Process maps may incorporate critical to quality (CTQ) factors, highlighting the elements most instrumental in driving customer satisfaction. 

Value stream mapping offers further insight into the flow of information and materials by pinpointing which activities can be classified as either value-added or non-value-added. This is a central component of waste identification but can also provide a roadmap for facilitating process improvements. 

Analyze 

The ‘Analyze’ phase leverages information gained through the previous ‘measure’ stage but shifts the focus to fully understanding that data and recognizing what it says about previously identified root causes. 

Pareto charts can play a pivotal part in this process, bringing clarity to the most significant concerns based on the Pareto principle — otherwise known as the 80/20 rule, which refers to “an observation that 80% of consequences come from 20% of the causes, indicating an unequal relationship between inputs and outputs.” With root causes successfully identified, hypothesis testing can confirm relationships between variables. Meanwhile, regression analysis helps to determine potential outcomes based on specific inputs. 

Additionally, this phase may refer to failure mode effects analysis (FMEA), which helps proactively address potential failure points. This may also involve assigning risk priority numbers. Utilizing this vast range of techniques, professionals can devise strategies that will be implemented during the ‘improve’ phase. 

Improve 

The ‘improve’ phase involves change and execution while leveraging the insights uncovered during previous phases (like ‘measure’ and ‘analyze’). Poor implementation could impede results in the later ‘control’ phase, so it is essential to navigate this activity with precision and clarity. A range of implementation strategies can be used to elevate this process, with some teams relying on a tool known as the PICK chart (possible, implement, challenge, kill) to prioritize actions based on their feasibility. 

Control 

The ‘control’ phase reveals how improvements achieved via the DMAIC model can be sustained over time. This may call for a control chart that tracks key variables and determines whether they remain within target ranges. Ideally, any deviations will be identified and addressed early on. 

Standard operating procedures (SOPs) provide clarification, detailing how improvements will be sustained on a day-to-day basis. This phase may also involve an analysis of replication opportunities, showing how findings from the entire DMAIC cycle can be leveraged to inform future process improvement efforts. 

Understanding and Implementing DMAIC 

There is no singular, straightforward way to navigate DMAIC. While this framework aims to bring clarity to process improvements, the sheer range of tools and techniques involved can seem overwhelming. This is where focused study can prove valuable.  

DMAIC and its associated techniques are covered in detail through Georgia Tech's Professional Master's in Manufacturing Leadership (PMML) — which uses immersive learning experiences to bring these concepts to life, plus a hybrid format to promote flexible learning solutions. In addition, you may select from short, non-credit courses from the Scheller College of Business through Georgia Tech Professional Education (GTPE) that cover the LSS Yellow Belt, Green Belt, and Black Belt. 

Embrace Lean Six Sigma Principles with Georgia Tech Professional Education 

Lean Six Sigma provides an impactful blueprint for driving change across industries. In manufacturing, this transformative methodology holds the secret to sustainable growth within a dynamic and highly competitive market. 

Georgia Tech Professional Education (GTPE) delivers the guidance and support needed to tackle complex manufacturing challenges. It all begins with pursuing a Professional Master's in Manufacturing Leadership (PMML) from Georgia Tech. Offering a deep dive into critical areas like production planning and supply chain strategy — plus a hybrid learning format — this program can help you earn in-demand credentials (such as Lean Six Sigma Black Belt Certification). To supplement your education, non-credit courses from the Scheller College of Business through GTPE include programs and certification in Lean Six Sigma Yellow Belt, LSS Green Belt, and LSS Black Belt. Request more information today to learn more.