The key principles of Six Sigma


The key principles of Six Sigma

Aim of Six Sigma

Six Sigma is an approach to reduce the defects in the processes of any kind. The motive of every business is to satisfy the customers and make a profit. These motives can be addressed by reducing the defects in the process. By reducing the defects, the business can produce more products and increase profit. By reducing variation in the process, the business can provide product or service whatever the customer needs.

Two Methodologies of Six Sigma

Six Sigma uses two methodologies to approach a problem. They are:

1. DMAIC –

The DMAIC methodology has 5 phases; Define Measure Analyse, Improve and Control. It is used to improve the existing process. In this methodology problem is identified, the impact of the problem is measured and the root cause of the problem is analyzed. Then the root cause is eliminated in the existing process and the process is controlled so that it does not go back to the previous state. This controls the variation in the process.


2. DMADV –

This methodology has 5 phases; Define Measure Analyse, Design and Verify. It is used to design the new process in such a way that no variation is there. This is called design for six sigma (DFSS). In this methodology problem is identified, the impact of the problem is measured and the root cause of the problem is analyzed. Then the system is designed eliminating the identified problem and verified.


DPMO – Target of every six sigma project

The target of every six sigma project is to achieve a metric of 3.4 defects per million opportunities. The six sigma methodologies aim to make the system more sophisticated in such a way that the process will not produce more than 3.4 defects per million opportunities. Target may not be achieved overnight or in a single project. It takes a series of projects at different levels of businesses, which involves all the stakeholders of the business.

Principles of Six Sigma

There are 5 key principles of Six Sigma:

1. Focus on Customer Requirements:

The initial phase in Six Sigma process is defining the “quality” from the point of customers. Every customer defines quality differently. A business needs to measure quality in a similar way its customers do. By addressing the needs of the customer business can define the quality to the customer.

2. Use data to identify the variation in the process:

Variations in the process are of two types; Special cause variation and Natural variation. Special cause variation is caused by external factors. Natural variation is random variation present in the process. Six Sigma aims to reduce the special cause variation. To identify the root cause of the variation, understating the process is necessary. The understanding of the process should be deep and extensive. Knowledge about the process cannot be gained unless it is studied. To understand the process clearly, detailed data about the process is important.

To collect detailed data:

  • Define the goals for data collection clearly
    • Identification of the data.
    • Define the reason for the data collection
    • Define the expected insight
  • Define the data collection method
  • Eliminate the error in the data collection by doing Measurement System Analysis
  • Define the Data collection plan

Data collection in the Six Sigma process includes interviewing with people, taking observations, and asking questions.

Once the data collection is finished, check whether the collected data gives the required knowledge to meet the objectives which were set up. If not, repeat the data collection plan and get more information. The process is repeated to find answers. Identify the potential root causes for the variation in the process and try to eliminate it with the help of collected data. After identifying the potential root causes, analyze it. To identify the significant root cause that makes the variation, use Statistical analysis.

3. Continually improving the process to eliminate the variation:

After identifying root causes, make changes to eliminate variation in the process. Thus the defects in the process are removed. Additionally, search for ways to remove steps that do not add value to the customer. This will eliminate waste in the process. Identify variation and eliminate it. Don’t wait for the variation to show itself. Collect data, talk to people, and study the data to identify variations in the process. variation may have become the routine because “that’s the way we’ve always done things.”

4. Involve people from different levels of management and process:

Six Sigma is formed on the foundation of good teams. The good teams comprise of peoples who take responsibility for the Six Sigma processes. The people on the team need training in Six Sigma’s methods. Forming a cross-functional team with peoples from different backgrounds will help identify variation.

For example, six sigma team from health care project consists of top management people, doctors, nurses, managers, people from operations and purchasing.

5. Be flexible and thorough:

Six Sigma requires adaptability from various points of view. The business’s management system needs to acknowledge positive changes. People should be motivated to accept the changes in the system to eliminate the variation. To motivate the employee, the benefits of the six sigma system should be made clear to all levels of employees. This will make the changes easily acceptable.

Six Sigma also requires reducing variation to be thorough. So understand all the aspects of a process—the steps, stakeholders, and methods involved. This will help to ensure that any new or updated process works.

The importance of Six Sigma Principles:

Six Sigma is such a popular approach for process management as it forms a way through which one can improve their processes. It is centrally a customer and product-driven approach. The main purpose of this approach is to avoid waste and delivering the product by meeting all the requirements of the customer thereby increasing customer satisfaction. To accurately analyze the process, Six Sigma requires precise data. The below goals also known as business success facts can be achieved by implementing Six Sigma in a company.

  • Increased Productivity
  • Increased Quality
  • Reduced Operation Cost
  • High Customer Satisfaction
  • Improved Employee Morale
  • Efficient Work environment


By implementing Six Sigma methodology, the business can reduce the variation in the process. With Six Sigma in the process, the business can focus clearly on customer requirement. It can adhere to customer requirements. By adhering to the customers’ requirement the business can improve its customer satisfaction. Highly satisfied customers bring more profits to the business. With the help of Six Sigma, the operation cost is reduced and it is converted to profit. It also improves the morale of the employees and comfortness of the workplace, this creates a happy and efficient workplace. This gives more productivity and quality to the product.