Six Sigma

Six Sigma is a structured, data-driven strategy for improving the quality of process results. It uses statistical methods to reduce variability in business processes to improve quality, efficiency and profitability.

Six Sigma is a systematic methodology that aims to improve business processes by reducing defects and process variability. Initiated by Motorola in the 1980s, it has since been widely adopted across various sectors, including manufacturing, healthcare, finance, and IT. The goal is to streamline processes to a level where defects are nearly non-existent – approximately 3.4 defects per million opportunities. Its data-driven nature separates it from other quality improvement methods, employing statistical tools and techniques for decision-making and problem-solving.

What is Six Sigma?

Six Sigma is an analytical approach that aims to improve business efficiency by minimizing errors and deviations in processes. It is based on a five-stage methodology: Define, Measure, Analyze, Improve and Control (DMAIC). Each phase plays a critical role. The define phase identifies the problem, the measure phase evaluates current process performance, the analyze phase identifies the root causes of defects, the improve phase provides solutions, and the control phase ensures the longevity of those improvements. The Six Sigma methodology is so flexible that it can be applied in a variety of business areas, from improving product quality in manufacturing to improving customer service in a call center.


The term “Six Sigma” comes from statistics and is used in statistical quality control, which evaluates process capability. Originally, it referred to the ability of manufacturing processes to produce a very high percentage of output within specifications. In “Six Sigma,” the number “six” refers to the standard deviation of the process from the mean or average. The “sigma” is a statistical term that measures process variation. A Six Sigma process is expected to be 99.99966% error-free, meaning that it produces only 3.4 errors per million opportunities.

Key concepts & Components

Some of the key concepts and components of Six Sigma are:

  • DMAIC: An acronym for Define, Measure, Analyze, Improve, Control; it is the core tool used to drive Six Sigma projects.
  • Defect: Anything that could lead to customer dissatisfaction.
  • Variation: What the customer sees and feels could potentially lead to dissatisfaction.
  • Control Charts: These are tools used to determine if a manufacturing or business process is in a state of statistical control.

Process, Use Cases or Applications

The Six Sigma process largely involves the DMAIC cycle. It begins with defining the problem, measuring the current situation, analyzing data to determine the root causes of problems, improving the process by implementing and reviewing corrective actions, and finally controlling the process to ensure the problem does not recur.

Six Sigma is used in a variety of industries. In manufacturing, it can be used to reduce the percentage of defective products. In healthcare, it can be used to reduce patient readmission rates. In finance, it can be used to reduce errors in data entry and processing.

History & Evolution

The concept of Six Sigma was first developed in Motorola in the 1980s to improve production processes. Bill Smith, an engineer at Motorola, is credited with its development. In the 1990s, Six Sigma gained widespread recognition when Jack Welch made it a central part of General Electric’s business strategy. Today, it is a globally recognized standard for process improvement and is used by companies of all sizes and industries.

Benefits, Challenges and Drawbacks of Six Sigma

Among the most important benefits of Six Sigma is the significant reduction of process variation and defects, resulting in high-quality products and services. This often leads to higher customer satisfaction and significant cost savings through reduced rework, scrap and warranty issues. Six Sigma also promotes a culture of continuous improvement and data-driven decision making.

However, implementing Six Sigma is also fraught with challenges. It requires a significant commitment of resources and time. It can be difficult to integrate it into the corporate culture, especially if it is resistant to change. The statistical tools and methods used in Six Sigma can be complex and require training to understand and properly implement.

Best practices & Strategies

To effectively implement Six Sigma, a company should secure the commitment of top management, as their support is critical to the initiative. Training employees on Six Sigma methods and principles is also important. Another best practice is to start with small projects to achieve quick results and then gradually tackle more complex processes.

Case studies

A notable example of the successful implementation of Six Sigma is General Electric (GE). In the mid-1990s, then-CEO Jack Welch implemented Six Sigma, and by the end of 2000, GE reported $2.5 billion in savings due to Six Sigma initiatives and significant investments.

On the other hand, 3M had mixed experiences with Six Sigma. While it initially led to cost savings and operational efficiencies, over time it was argued that the focus on defect reduction stifled creativity and innovation-crucial elements for a company known for its products such as Post-it notes and tape.

Future Trends and Outlook

Six Sigma continues to be a dominant force in process improvement across many industries. Its future appears to be moving toward integration with other methodologies such as Lean (Lean Six Sigma) and Big Data Analytics to enable more holistic and data-driven decision-making processes. As companies continue to emphasize efficiency, quality, and customer satisfaction, the principles of Six Sigma are likely to remain relevant.

Frequently Asked Questions about Six Sigma

Which industries can apply Six Sigma?

Six Sigma can be applied in any industry that relies on repeatable processes. This includes, but is not limited to, manufacturing, healthcare, IT, finance, and logistics.

How does Six Sigma differ from Lean?

Although both Six Sigma and Lean aim to eliminate waste and improve efficiency, they focus on different types of waste. Lean is about eliminating non-value-added activities (waste), while Six Sigma focuses on reducing variation and improving process quality.

What does a “Six Sigma level” mean?

A Six Sigma level is a measure of quality and efficiency. For a process to reach the Six Sigma level, it must produce no more than 3.4 defects per million opportunities.

What is DMAIC in Six Sigma?

DMAIC is a data-driven improvement cycle used in Six Sigma. It stands for Define, Measure, Analyze, Improve and Control, which are the key steps in the process improvement journey.

Is Six Sigma certification worth it?

For many professionals, Six Sigma certification can be a worthwhile investment. It proves that you know about efficient business processes, data analysis and project management – skills that are in demand in many industries.

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