Lean Six Sigma: Guide to Improve Processes

Milthon Lujan Monja

In a competitive world, companies constantly seek ways to enhance their processes to increase efficiency, reduce costs, and improve the quality of their products and services. Lean Six Sigma (LSS) is a process improvement methodology that combines the principles of Lean Manufacturing and Six Sigma to help organizations achieve these goals.

Lean Six Sigma has emerged as a dynamic approach to achieve operational excellence and continuous improvement within organizations, facilitating the transition to Industry 4.0 (Antony et al., 2023) and thereby ensuring the competitiveness of implementing companies.

But what exactly is LSS, and how can it be successfully implemented? In this comprehensive guide, we will uncover the secrets of Lean Six Sigma and provide a step-by-step framework for implementation, from defining the problem and setting objectives to analyzing data, implementing solutions, and monitoring results. We’ll offer practical tips, real-life examples, and best practices to help you navigate the implementation process with confidence.

What is Lean Six Sigma?

Lean Six Sigma (LSS) combines two powerful methodologies—Lean and Six Sigma. It can be defined as a data-driven methodology that focuses on eliminating waste and variation in processes. The goal is to create or optimize a process that is efficient, effective, and predictable, ultimately improving overall quality and leading to increased customer satisfaction and profitability.

The combination of Lean and Six Sigma provides a comprehensive set of tools to enhance the speed and effectiveness of processes (Madhani, 2020) across various industries such as manufacturing, healthcare, finance, and more.

Lean Six Sigma: Convergence of Lean and Six Sigma Approaches. Source: Madhani (2020); IUP Journal of Operations Management.
Lean Six Sigma: Convergence of Lean and Six Sigma Approaches. Source: Madhani (2020); IUP Journal of Operations Management.

History of Lean Six Sigma

The history of Lean Six Sigma is a fusion of two approaches: Six Sigma and Lean Manufacturing. Each has its trajectory before converging into the powerful methodology we know today.

Six Sigma:

  • 1980: Emerged at Motorola driven by engineer Bill Smith to drastically reduce defects in products, target an ambitious goal: 3.4 defects per million opportunities (DPMO).
  • 1990s: General Electric adopts Six Sigma under Jack Welch’s leadership, heavily investing in training and achieving notable improvements in costs and efficiency.
  • Late 1990s and early 2000s: Six Sigma becomes popular in various industries, with certifications like Black and Green Belts recognizing expertise.

Lean Manufacturing:

  • Early 20th century: Frederick Taylor and Henry Ford drove efficiency in industrial production with techniques like the assembly line.
  • 1950s: Toyota developed the Toyota Production System (TPS), which focused on waste elimination and continuous improvement.
  • 1980s: TPS gains international recognition and is labeled “Lean Manufacturing.”

Convergence: Lean Six Sigma:

  • Late 1990s: Recognizing the strengths of both methodologies, Lean (eliminating waste) and Six Sigma (reducing variation) principles merge to create Lean Six Sigma (LSS).
  • 2000s: Lean Six Sigma gains ground in various sectors, from automotive to healthcare and technology.
  • Present: LSS continues to evolve, adapting to new technologies and market needs.

Principles of Lean Six Sigma

Lean Six Sigma is based on a set of principles guiding its implementation. Rooted in continuous improvement, waste elimination, and customer focus, these principles unlock the full potential of LSS.

The five principles of Lean Six Sigma are:

  1. Customer Focus: LSS aims to meet customer needs, understand what customers truly value, and align processes to deliver that value.
  2. Identification and Elimination of Waste: Waste includes any activity that does not add value to the product or service.
  3. Continuous Improvement: Processes must be continuously improved to achieve excellence, even if a process seems to be working well.
  4. Measurement and Analysis: Processes need to be measured and analyzed to identify areas for improvement, emphasizing data-based decision-making.
  5. Teamwork: LSS is a team effort requiring the participation of all employees.
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Benefits of Lean Six Sigma

Executives often ask, “What is Lean Six Sigma for?” Tampubolon and Purba (2021) report that LSS helps organizations improve competitiveness, enhance quality, reduce costs, increase customer satisfaction, boost productivity, and raise employee morale.

The Lean Six Sigma methodology offers several benefits to organizations, including:

  • Quality Improvement: Focuses on reducing defects and enhancing quality in product or service delivery, leading to increased customer satisfaction.
  • Cost Reduction: Saves money by eliminating waste, and identifying and removing activities that do not add value to the customer.
  • Efficiency Improvement: Enhances operational efficiency by eliminating redundant activities, minimizing cycle times, and optimizing resources, leading to increased productivity.
  • Customer Satisfaction Improvement: Directs activities toward customer needs and expectations, ensuring delivered products or services meet their requirements.
  • Data-Driven Decision-Making: Utilizes statistical tools and data analysis to support decision-making, ensuring informed and accurate approaches.

In summary, Lean Six Sigma serves as a structured and effective framework for continuous improvement, offering tangible benefits in terms of operational efficiency, product or service quality, and customer satisfaction. The LSS methodology is applicable across various sectors and has proven to be a valuable tool for organizations seeking to optimize processes and achieve consistent, high-quality results.

Requirements for Implementing Lean Six Sigma

If you want to implement LSS in your organization, the main requirements are:

  1. Leadership Commitment: Crucial support from top management to allocate resources and create a culture of continuous improvement.
  2. Team Training: Formation of a Lean Six Sigma knowledgeable team to lead improvement projects.
  3. Project Selection: Identification of areas for improvement with potentially significant impact.
  4. Availability of Resources: Time, budget, and tools to carry out the projects.

DMAIC Methodology in LSS

The implementation of Lean Six Sigma requires commitment from leadership and the involvement of all employees. It follows a structured problem-solving methodology known as DMAIC, which stands for Define, Measure, Analyze, Improve, and Control. This methodology provides a clear roadmap for implementing LSS projects and achieving sustainable improvements.

The implementation process typically involves the following steps:

  1. Preparation: Define the implementation objectives and create a leadership team.
  2. Assessment: Evaluate current processes to identify areas for improvement.
  3. Improvement: Implement changes to enhance processes.
  4. Control: Monitor processes to ensure that improvements are maintained.

A detailed description of the DMAIC methodology and its variants can be found in our article on Six Sigma (Spanish).

Roles in Lean Six Sigma

Lean Six Sigma defines several key roles within its implementation and continuous improvement system. These roles have differentiated responsibilities to ensure project success and methodology adoption within the organization. Here’s a breakdown:

C-Suite Level

  • Champion: Executive sponsor of LSS in the organization, providing strategic vision, resources, and support to projects.
  • Executive Sponsor: Represents management in the Lean Six Sigma committee, oversees progress, and makes strategic decisions.

Leadership/Management Level

  • Master Black Belt (MBB): Expert with extensive experience in the methodology. Provides mentoring to Black Belts, leads complex projects, and develops LSS strategy in the organization.
  • Black Belt (BB): Technical leader of improvement projects, expert in DMAIC and key tools. Applies the methodology to solve complex problems and improve processes.
  • Green Belt (GB): Trained professional in LSS participating in projects led by Black Belts. Conducts data analysis, implements solutions, and contributes to continuous improvement.

Operational Level

  • Yellow Belt: Individual with basic knowledge of Lean Six Sigma. Participates in process improvement activities within their team or department.
  • Team Member: All employees in the organization. Encouraged to identify improvement opportunities, participate in projects, and contribute to the Lean Six Sigma culture.

In addition to these main roles, other supporting positions may exist:

  • Instructor/Trainer: Responsible for Lean Six Sigma training at different levels.
  • Data Analyst: Expert in statistical analysis and quality tools supporting Black Belts in their projects.
  • Change Management Specialist: Supports the organization in adopting the cultural change that comes with LSS.
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Each organization can adapt these roles and responsibilities to its specific needs and size. The key is to have a trained and committed team to drive continuous improvement through LSS.

Lean Six Sigma Tools

Lean Six Sigma utilizes a variety of tools to improve processes, including:

  • Value Stream Maps: Used to identify steps in a process and areas for improvement.
  • Cause and Effect Diagrams: Used to identify the root causes of a problem.
  • Pareto Analysis: Used to identify the most significant problems that need addressing.
  • Design of Experiments: Used to test different solutions to a problem.

Lean Six Sigma Certifications

Certification in Lean Six Sigma is a formal recognition of skills and knowledge in applying the LSS methodology to improve processes and promote operational efficiency in an organization. These certifications are structured at different levels, each representing a degree of experience and competence in the methodology. Common certification levels in Lean Six Sigma include:

Yellow Belt

  • Introduction to LSS principles and basic concepts.
  • Participation in projects as a team member.
  • Fundamental knowledge of the methodology and its application.

Green Belt:

  • In-depth understanding of Lean Six Sigma.
  • Leadership of process improvement projects under supervision.
  • Application of specific LSS tools and techniques.

Black Belt:

  • Advanced mastery of LSS.
  • Independent leadership of process improvement projects.
  • Extensive application of statistical and analysis tools.

Master Black Belt:

  • Leadership level and expert experience.
  • Supervision of multiple projects and teams.
  • Development of strategies for Lean Six Sigma implementation across the organization.

Achieving a Lean Six Sigma certification typically involves participation in a training program and passing an exam that assesses understanding and application of LSS principles and tools. These certifications are globally recognized and may be offered by organizations specialized in Lean Six Sigma training.

Examples of Lean Six Sigma

The adoption of Lean Six Sigma as a continuous improvement methodology has grown significantly in the manufacturing sector and some service sectors, such as healthcare and higher education, over the last decade (Patel et al., 2021). Below are some examples of the application of LSS:

  • Manufacturing: Streamlining production lines, reducing defects, and improving performance. Sharma et al., (2022) report the application of LSS to enhance manufacturing efficiency in Indian companies, resulting in a 53% reduction in defect rates.
  • Service Industries: Reducing wait times, improving customer satisfaction, and optimizing internal processes.
  • Healthcare: Enhancing patient care, reducing errors, and improving operational efficiency. Vaishnavi and Suresh (2020) emphasize that a customer-oriented and goal-management culture are key readiness factors for implementing the LSS methodology. Scala et al., (2021) report the use of Lean Six Sigma to reduce patient waiting times in a hospital.
  • Finance: Minimizing errors, expediting transactions, and reducing processing times. Madhani (2020) highlights that LSS implementation is a key business strategy to improve the quality and productivity of financial organizations, helping them transform from operational to tactical, and ultimately, to strategic functions.

Green Lean Six Sigma

Manufacturing industries contribute to environmental pollution, posing a threat to environmental sustainability. To address this issue, Green Lean Six Sigma has emerged.

Green Lean Six Sigma is an ecological approach that mitigates carbon footprint and produces high-specification products and It is applied to improve the environmental sustainability of operations (Gholami et al., 2021).

Kaswan et al., (2023) propose a conceptual framework that includes guidelines from project selection to solution maintenance.

Lean Six Sigma vs. Six Sigma

The following comparative table provides an overview of the main differences between Lean Six Sigma and Six Sigma. It’s important to note that while Lean Six Sigma incorporates Lean and Six Sigma principles, traditional Six Sigma primarily focuses on quality improvement through statistical methods. The choice between the two approaches depends on the specific needs and goals of an organization.

Comparative Table between Lean Six Sigma vs. Six Sigma

AspectLean Six SigmaSix Sigma
PhilosophyIntegrates Lean principles (waste reduction) with Six SigmaPrimarily focused on eliminating defects and variability
ApproachComprehensive, addressing both speed and qualityConcentrated on improving quality through statistical methods
MethodologyIncorporates DMAIC (Define, Measure, Analyze, Improve, Control)Mainly follows the DMAIC methodology
Waste ReductionEmphasizes the elimination of waste in processesMay not explicitly focus on minimizing non-value-adding activities
FlexibilityAdaptable to various industries and processesOriginally developed for manufacturing but adapted to diverse sectors
Speed vs. AccuracyPrioritizes speed without compromising qualityEmphasizes precision and quality with possible trade-offs in speed
Tools and TechniquesUses Lean tools and Six Sigma statistical tools: Value Stream Maps, Cause and Effect Diagrams, Pareto Analysis, Design of ExperimentsPrimarily relies on statistical tools for data-driven decision-making: Control charts, Process capability analysis, Design of Experiments
Cultural ImpactFosters a culture of continuous improvementCultivates a culture of data-driven decision-making and a focus on quality
CertificationsOffers Lean Six Sigma certifications at various levelsTraditionally associated with Six Sigma Green and Black Belt certifications
ScopeAddresses both the efficiency and effectiveness of processesPrimarily focuses on improving effectiveness in processes

Kaizen and Lean Six Sigma

The following comparative table provides an overview of the key aspects of Kaizen and Lean Six Sigma, highlighting the differences and similarities between both approaches for continuous improvement in an organization. It is important to note that both methods can be complementary, and the choice between them may depend on organizational culture, specific goals, and implementation preferences.

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Comparative Table of Kaizen and Lean Six Sigma:

AspectKaizenLean Six Sigma
Main FocusContinuous improvement, incremental changesVariability reduction, structured improvement
Employee InvolvementEmphasizes participation of all employeesInvolves employees, but with a more structured approach
Organizational ChangeFocuses on small and gradual changesMay include more significant and structured changes
Improvement CycleEmphasis on rapid improvement cyclesFollows the DMAIC cycle (Define, Measure, Analyze, Improve, Control)
Key Tools5S, Gemba Walks, PDCAValue Stream Mapping, Statistical Analysis, Quality Tools
Problem ApproachFocuses on direct observation and practical solutionsUtilizes statistical analysis to identify and address root causes
Organizational CultureCulture of continuous improvement and participationMay require a cultural shift towards data-driven decision-making
Waste ReductionSeeks to eliminate waste constantlyFocused on waste elimination through data analysis
Application ScopeBroad, applicable to all levels and processesCan be applied to various processes but with a more structured approach
Methodological StructureLess structured, flexibleFollows a structured methodology (DMAIC)


Lean Six Sigma is a powerful tool that can help organizations improve their processes and achieve their goals. Implementing LSS requires commitment from leadership and the involvement of all employees, but it can provide a range of benefits to the organization.

It is evident that the Lean Six Sigma methodology is not just a set of tools; it is a mindset that fosters a culture of continuous improvement. Whether you are an experienced professional or just starting your LSS journey, the explored principles are the key to unlocking excellence in your organization.


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Antony, J., McDermott, O., Powell, D. and Sony, M. (2023), “The evolution and future of lean Six Sigma 4.0“, The TQM Journal, Vol. 35 No. 4, pp. 1030-1047. https://doi.org/10.1108/TQM-04-2022-0135

Gholami, H., Jamil, N., Mat Saman, M. Z., Streimikiene, D., Sharif, S., & Zakuan, N. (2021). The application of green lean six sigma. Business Strategy and the Environment, 30(4), 1913-1931.

Kaswan, M.S., Rathi, R., Cross, J., Garza-Reyes, J.A., Antony, J. and Yadav, V. (2023), “Integrating Green Lean Six Sigma and industry 4.0: a conceptual framework“, Journal of Manufacturing Technology Management, Vol. 34 No. 1, pp. 87-121. https://doi.org/10.1108/JMTM-03-2022-0115

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Scala, Arianna, Alfonso Maria Ponsiglione, Ilaria Loperto, Antonio Della Vecchia, Anna Borrelli, Giuseppe Russo, Maria Triassi, and Giovanni Improta. 2021. “Lean Six Sigma Approach for Reducing Length of Hospital Stay for Patients with Femur Fracture in a University Hospital” International Journal of Environmental Research and Public Health 18, no. 6: 2843. https://doi.org/10.3390/ijerph18062843

Sharma, A., Bhanot, N., Gupta, A. and Trehan, R. (2022), “Application of Lean Six Sigma framework for improving manufacturing efficiency: a case study in Indian context“, International Journal of Productivity and Performance Management, Vol. 71 No. 5, pp. 1561-1589. https://doi.org/10.1108/IJPPM-05-2020-0223

Tampubolon, S., & Purba, H. H. (2021). Lean six sigma implementation, a systematic literature review. International Journal of Production Management and Engineering, 9(2), 125–139. https://doi.org/10.4995/ijpme.2021.14561

Vaishnavi, V. and Suresh, M. (2020), “Modelling of readiness factors for the implementation of Lean Six Sigma in healthcare organizations“, International Journal of Lean Six Sigma, Vol. 11 No. 4, pp. 597-633. https://doi.org/10.1108/IJLSS-12-2017-0146