Six Sigma Simplified: Understanding Its Principles for Business Excellence

Six Sigma Principles

Six Sigma is a set of management techniques developed by American engineer Bill Smith in 1986 while working at Motorola to boost the company’s profits. In the first 20 years alone, this data-driven approach to quality control saved Motorola $17 billion. Many Fortune 500 companies, such as General Electric, Microsoft, and Honeywell, have hired and trained employees and consultants with a Six Sigma certification to drive significant cost savings.

The method’s principles harmonize organizational improvement, seamlessly orchestrating data-driven precision, process optimization, and relentless pursuit of improved quality. Six Sigma principles work synergistically to enhance and transform organizations into agile, high-performing entities, achieving harmony between excellence and continuous improvement. By significantly reducing the probability of error or defect, organizations use Six Sigma to deliver high-quality products and services in the most efficient way possible.

Over time, Six Sigma absorbed elements of Lean manufacturing, which greatly enhanced the methodology and created “Lean Six Sigma.” Now, if you look at the Six Sigma White Belt Body of Knowledge, it includes most of the key lean concepts.

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Six Core Principles of Six Sigma

Data-driven decision-making sits at the heart of Six Sigma. Organizations collect and analyze data to identify root causes of problems and make informed decisions about process improvements. Data tells us why a process works (or why it doesn’t). With this information, organizations can improve their offerings to meet customer needs better.

  1. Improve Customer Satisfaction
  2. Process Focus
  3. Remove Variation from Process
  4. Involve and Equip the People in the Process
  5. Make Systematic Decisions Based on Data
  6. Aim for Continuous Improvement

1. Improve Customer Satisfaction

The ultimate goal of Six Sigma is delivering business value as defined by the customer. That means enhancing customer satisfaction by consistently delivering products or services that meet or exceed customer expectations. To do that, teams analyze processes for potential improvement, quantify the costs, and determine if the benefits warrant the investment.

This principle strongly emphasizes understanding customer needs and expectations. By gathering customer requirements, preferences, and feedback data, organizations can align their processes to deliver products or services that satisfy customers.

2. Process Focus

Detailed process mapping plays a crucial role in the success of Six Sigma initiatives by providing a comprehensive understanding of the current state of processes and facilitating targeted improvements. Six Sigma professionals use graphs and flow charts to illustrate the details of the process and guide them in decision-making. This visual breakdown makes identifying strengths and weaknesses in a current process easier by pinpointing the performance of specific steps.

To create a process map, you must first define the process focus and then outline the major steps and stages from beginning to end. Bring together people from different departments involved so you can get the whole picture. Document each input, output, and the flow of materials or information from one step to the next. As the team collects data

3. Remove Variation from Processes

Six Sigma looks at two types of process variation: special cause variation and common cause (natural) variation. Common cause variation refers to the inherent variability in a process over time, such as fluctuations in materials, environmental conditions, equipment performance, or operator behavior. Special cause variation refers to variability in a process caused by specific identifiable factors or events that are not part of the usual, stable operation of the process. These factors are usually external or are some anomaly or error that disrupts the normal function of a process.

Six Sigma relies on statistical process control (SPC) to understand and manage real-time variability in processes. Control charts monitor process performance and detect the presence of special cause variation, allowing organizations to take corrective actions and maintain process stability. Additionally, DMAIC (Define, Measure, Analyze, Improve, Control), a structured problem-solving methodology, provides a systematic approach to identify, analyze, and mitigate sources of variation, leading to more stable and predictable process performance. We’ll explore this more in the next section.

4. Involve and Equip the People in the Process

Seasoned pros often say Six Sigma projects will only succeed if the organization has buy-in from the top down. That means the whole team needs to be involved and trained in the Six Sigma discipline to assume their appropriate role in each project. Just like a band of musicians needs to be in rhythm and harmony together, every role in a Six Sigma project is crucial to its success.

Roles and Responsibilities Within a Six Sigma Project:

  • Executives: Establish the focus of Six Sigma within the overall organizational goals
  • Champion: Communicate the organization’s vision, mission, and goals to create an organizational deployment plan and identify individual projects.
  • Master Black Belt: Oversee an organization’s whole Six Sigma program and is the primary internal consultant. Train and coach Black Belts and Green Belts and develop key metrics and strategic direction.
  • Black Belt: Run individual projects and manage Green and Yellow Belts.
  • Green Belt: Assist with data collection and analysis
  • Yellow Belt: Acts as a support person for the project team.
  • White Belt: Support Six Sigma projects as needed but are not necessarily part of the project team.

5. Make Systematic Decisions Based on Data

Six Sigma uses verifiable data and statistics to make decisions that can help organizations achieve measurable profit gains. It uses data to tangibly improve the quality of products and services, increasing customer satisfaction while reducing costs. A Six Sigma project aims to create a process that is 99.99966% free of defects (or to have fewer than 3.4 errors in one million opportunities).

Both quantitative and qualitative data are crucial to a comprehensive understanding of process performance. You can only remove variations and defects knowing the whole picture. Quantitative analysis provides objective, statistical insights into process performance and variation. In contrast, qualitative data analysis complements this by offering a deeper contextual understanding and insights into human behaviors and organizational dynamics.

6. Aim for Continuous Improvement

Six Sigma remains effective nearly forty years later because it emphasizes sustained improvement. Organizations that use Six Sigma don’t just fix a process and move on. They continue monitoring process improvements and make small, incremental changes to ensure they always perform at their best. Continuous improvement is especially important as technology continues to advance rapidly, thereby constantly introducing new opportunities to increase efficiency and quality.

To maintain momentum in Six Sigma initiatives, senior leadership has to remain fully committed to the Six Sigma program and actively support improvement efforts. It is critical to ingrain continuous improvement into your organizational culture, values, and practices and reward employees who contribute to process excellence and innovation.

Six Sigma Methodologies

Two methods are critical to the success of every Six Sigma project. The first is the DMAIC approach to problem-solving (Define, Measure, Analyze, Improve, Control). DMAIC projects, which typically last about four months, are used to improve existing business processes. This five-step method includes the following stages:

  • Define: Identify the problem, the improvement opportunity, the project goals, and internal and external customer requirements. Then, teams can move on and create a map illustrating how they will fix the issue.
  • Measure: Collect data and quantify the problem to measure performance and evaluate improvement.
  • Analyze: Use the data to investigate and understand the variables impacting the problem to determine what drives the defect at the center of the project.
  • Improve: Run experiments to learn how to implement the desired improvements and eliminate the underlying cause of the defect.
  • Control: Measure performance to ensure the newly improved process is successful. If any deviations from the previously targeted improvements need correction, create a quality control plan to maintain the process improvements.

The second project methodology is Define, Measure, Analyze, Design, Verify (DMADV) for projects creating a new product or process or dramatically overhauling an existing one. DMADV includes the same first three steps as DMAIC but changes the last two to Design and Verify. 

  • Design: Create high-level designs for the new process or product so the team can identify unforeseen errors and make additional modifications as necessary.
  • Verify: Review the new implementation with stakeholders to verify its effectiveness once deployed.


Six Sigma continues to influence business strategies by promoting cultures of continuous improvement, data-driven decision-making, and customer-centricity. It has kept pace with the digital age by evolving to Lean Six Sigma so organizations can continue optimizing products and services in the digital age. Industries will continue to change, but Six Sigma principles will remain. Organizations need trained experts with a Six Sigma certification ready to drive efficiency, quality, and customer satisfaction.

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