Six Sigma is a set of approaches, techniques, and tools to improve the capability of business processes. This increase in performance and decrease in process variation helps lead to defect reduction and improvement in profits, employee morale, and quality of products or services. A Six Sigma process is one in which 99.99966% of all opportunities to produce some features of a part are statistically expected to be free of defects.

The essential goal of Six Sigma is to eliminate defects and waste, thereby improving quality and efficiency, by streamlining and improving business processes. Manufacturing was the original focus. However, business executives discovered that Six Sigma could apply throughout all aspects of a business infrastructure from the sales process to customer support.

“The relevant question is not simply what shall we do tomorrow, but rather what shall we do today in order to get ready for tomorrow.”
Peter Drucker

Six Sigma Roots 

Six Sigma has its roots in a 19th Century mathematical theory but found its way into mainstream business science through the efforts of Bill Smith, an engineer, at Motorola in the 1980s. Jack Welch made it mission-critical to the business strategy at General Electric in 1995. Now recognized as one of the distinguished methodological practices for improving customer satisfaction and improving business processes, Six Sigma has been refined and perfected over the years into what we use today as Six Sigma.

Six Sigma Value Outcomes 

Six Sigma strategies improve the quality of process output by identifying and eliminating the sources of defects and minimizing variability in the manufacturing and business processes. It uses a set of quality management methods, primarily empirical, statistical methods, and creates an infrastructure of employees who are recognized specialists in these methods. Each Six Sigma project carried out follows a precise and defined sequence of steps with specific value targets, such as:

  • Decrease operating costs.
  • Improve profitability.
  • Increase customer satisfaction.
  • Increase productivity.
  • Lessen pollution.
  • Reduce process cycle time.

Six Sigma Characteristics

The key Six Sigma characteristics include:

  • View business work as processes that can be defined, measured, analyzed, improved, and controlled. Methods require inputs (x) and produce outputs (y). If you control the data, you will manage the outputs. This formula – y = f(x).
  • Use methodology – DMAIC (Define, Measure, Analyze, Improve and Control) or DMADV (Define, Measure, Analyze, Design, Verify)
  • Use qualitative and quantitative techniques and tools to drive process improvement, including Statistical Process Control (SPC), control charts, failure mode, and effects analysis, and process mapping.
  • Receive a commitment from the entire organization, principally from executive management.
  • Support performance metric goal of 3.4 defects per million opportunities (accounting for a 1.5-sigma shift in the mean). This metric supports process improvement with continuous efforts to the point where they produce stable and predictable results.

 Six Sigma Methodologies 

There are two primary recognized Six Sigma methodologies as outlined below:


DMAIC is used primarily for improving existing business processes.

  1. Define the problem and project goals.
  2. Measure in detail the various aspects of the current process.
  3. Analyze data to identify the process of root defects.
  4. Improve the targeted process.
  5. Control how the process will work/flow in the future.


DMADV is used to create new processes and new products or services.

  1. Define opportunity and project goals.
  2. Measure critical components of the process and product capabilities.
  3. Analyze data and develop various designs for the process; selecting an optimum method.
  4. Design and test process.
  5. Verify process design with simulations and pilot programs.

The Lean Approach

Similar to  Six Sigma, Lean is an approach used to streamline manufacturing and production processes. The main emphasis of Lean is on cutting out unnecessary and wasteful steps in the creation of a product so that only steps that directly add value to the product are incorporated.

As far as Lean methodology is concerned, the only way to determine if something has value or not is to consider whether a customer would be willing to pay for it. Any part of the production process that does not add value is removed, leaving a highly streamlined and profitable operation in place that will flow seamlessly, smoothly, and efficiently.

Difference between Lean and Six Sigma

Fundamentally, Six Sigma and Lean have the same objective. They both seek to eradicate waste and create the most efficient system possible. However, they take different approaches toward how they achieve this goal. Generally, the main difference between Lean and Six Sigma is that they identify the root cause of waste differently.

The Lean approach views waste is resulting from unnecessary steps in the production process that do not add value to the finished product, while the Six Sigma approach asserts that waste results from variation within the process. Both methods have been successful in practice, which is why both Lean and Six Sigma have been valuable in improving overall business performance in a variety of fields. These two disciplines have proven to be extraordinarily successful when working in tandem – hence the creation of Lean Six Sigma.


Today, Six Sigma plays a vital role in the leadership of an organization, and its wide-scale implementation can help a company to achieve real and measurable results.

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