The House of Lean Six Sigma

What is Six Sigma?

Six Sigma is a disciplined and data-driven methodology used in business and manufacturing processes to improve the quality of products and services while reducing defects and variability. Six Sigma aims to achieve near-perfect performance by identifying and eliminating process errors, defects, and inefficiencies.

The term “Six Sigma” comes from statistical jargon, where “sigma” (σ) represents a standard deviation, a measure of variability. The “six” in Six Sigma refers to achieving a process capability where the process variation is so tiny that it produces fewer than 3.4 defects per million opportunities (DPMO), making it highly reliable and consistent.

The Six Sigma approach also leads to improved profits, increased employee morale, and higher customer satisfaction.

Learn more about the Six Sigma methodology and philosophy.

How one company visualized their Six Sigma implementation

Allergan, a global specialty pharmaceutical company, has over 5,000 employees, 33 commercial locations, four research and development facilities, and three manufacturing plants. The Waco plant has been pioneering Six Sigma and lean manufacturing initiatives for company operations worldwide.

Allergan created this House of Lean Six Sigma infographic, proposing various methodologies for understanding the root problem, including regression analysis, process mapping, and control charts.  

The House contains six elements in its carefully constructed framing:

  • Foundational Tools provide a supportive platform to build the rest of the house.
  • Supporting Tools comprise an overarching “roof.”
  • Four “rooms” covering four possible problem scenarios:
    • Problem Known, Cause Known.
    • Problem Known, Cause Unknown.
    • Problem Suspected, But Unknown.
    • Problem Unknown and Recognized.

In this series of posts, we will deconstruct the graphic and provide an overview of this vast array of valuable tools. 

In this first installment, let’s cover the Foundational and Supporting Tools. Subsequent posts will dig into each of the four rooms. 

Foundational Tools


Originating from Japanese terminology, 5S represents a structured method for organizing, cleaning, and maintaining a workplace. The five S’s stand for Seiri (Sort), Seiton (Set in order), Seiso (Shine), Seiketsu (Standardize), and Shitsuke (Sustain). This method creates a visually intuitive and efficient workspace, reducing waste and non-value-added activities and promoting safety and discipline.

Visual Controls

In Lean Six Sigma, visual controls display information about process performance, goals, standards, and deviations in a way that can be quickly and easily understood. These include signs, charts, color coding, or floor marking. The main goal of visual controls is to make the system’s status apparent to everyone, fostering proactive problem-solving and continuous improvement.

TPM (Total Productive Maintenance)

Total Productive Maintenance (TPM) is a proactive approach that focuses on maintaining and improving the integrity of production and quality systems through the machines, equipment, processes, and employees that add business value. TPM seeks to maximize equipment effectiveness, eliminate breakdowns, and reduce production defects by involving all employees, from top management to frontline operators.

Key Metrics

Key metrics – also referred to as key performance indicators (KPIs) – are quantifiable measurements that evaluate the success of an organization, a specific activity, or a process in meeting its objectives. In the Lean Six Sigma framework, key metrics assess the effectiveness of process improvements and control measures, offering valuable insights into performance and guiding data-driven decision-making.

Dashboard Displays

Dashboard displays are an integral part of Lean Six Sigma’s data-driven approach. They provide a concise, visual representation of key metrics and progress toward goals. Dashboards can display real-time data, enabling immediate response to changes or issues. By visualizing complex data, dashboard displays help in monitoring process performance.

Supporting Tools

Gage R&R 

Gage Repeatability and Reproducibility (Gage R&R) is a statistical tool used in the Measure phase of Lean Six Sigma to evaluate the measurement variation coming from the measurement system itself. This includes both the precision of the measurement device (repeatability) and the consistency of the results across different operators (reproducibility). It helps ensure that the data used for analysis is reliable.

Affinity Diagrams

Affinity Diagrams are tools often used in the Analyze phase of Lean Six Sigma for organizing a large amount of data into meaningful categories based on their natural relationships. This tool helps teams identify patterns and themes in the data, promoting more effective problem-solving and decision-making.

Team Chartering

Team Chartering is a foundational step in the Define phase of Lean Six Sigma. It involves defining the team’s purpose, the problem it’s trying to solve, the scope of its work, its goals, and the roles of each team member. A well-crafted team charter provides clarity and direction, helping to align the team and stakeholders and drive project success.

VOC (Voice of the Customer)

Voice of the Customer (VOC) is a process used in Lean Six Sigma to capture customers’ expectations, preferences, and aversions. By listening to the VOC, organizations can better understand what customers value and focus their improvement efforts on areas that will increase customer satisfaction.

Pareto Analysis

Pareto Analysis is a technique used for prioritizing problems or causes of problems. It’s based on the Pareto Principle, also known as the 80/20 rule, which suggests that a small number of causes are responsible for a large percentage of problems. By identifying these high-impact causes, teams can focus their improvement efforts on where they will have the most impact.

Force Field Analysis

Force Field Analysis is a decision-making tool used in Lean Six Sigma to analyze the forces for and against a change. By identifying and weighing these forces, teams can develop strategies to strengthen the forces supporting change and reduce the forces resisting it, increasing the likelihood of successful implementation.


Brainstorming is a creativity technique used to generate many ideas to solve a problem. It promotes free thinking and open communication within the team, fostering a culture of continuous improvement.

RACI (Responsible, Accountable, Consulted, Informed)

RACI is a tool used to clarify roles and responsibilities in cross-functional processes. By defining who is responsible for executing tasks, who is accountable for ensuring tasks are accomplished, who needs to be consulted, and who should be informed about progress, the RACI chart helps reduce confusion and improve coordination.

Project Definition Form

The Project Definition Form is a key document in the Define phase of Lean Six Sigma. It provides an overview of the project, including its purpose, scope, objectives, team members, and timeline. The form serves as a guide for the team throughout the project and helps ensure alignment with stakeholders.


While these tools are an integral part of a Six Sigma program, they can also be implemented as standalone quality improvement actions or as part of other process improvement initiatives. Return for future articles in this series to learn more about the other tools that support the House of Lean Six Sigma.

Process improvement is a way of life at Thurman Co.

In addition to an in-house culture that thrives on ownership and responsibility throughout our team, we help businesses manage projects to significantly impact their success and growth, which often includes analyzing and improving processes.

When you’re ready to put your project in the hands of a trusted professional organization, contact us to learn more about working together.

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