What is Six Sigma

Rasel T.


Six sigma is one of the most effective management tools used to increase the performance of business processes of an organization. It helps management reduce the number of defects and product variations. Every product defect has a cost associated with it including losing clients, replacing or repairing products and losing efficiency in business processes.

Six Sigma was first developed by Motorola in 1986 to identify and measure defects at the granular level. This resulted in tremendous improvement in several of Motorola's products, leading to a global revolution in how business processes are analyzed and ameliorated. The Six Sigma methodology uses statistical tools to improve quality by detecting causes of defects and reducing variations in manufacturing processes.

What does Six Sigma Mean?

Six Sigma is a statistical term that measures variations (standard deviations - σ) in data from the mean value (µ) of a dataset. Practically speaking, it calculates how many defective products are produced while identifying the root cause(s) of the defects. The higher the sigma score, the better the performance of the manufacturing process will be. Using this process, as high as 99.99966% of the manufactured products are expected to be free of defects. 

Methodologies of Six Sigma

DMAIC and DMADV are the two methodologies of Six Sigma and are based on two specific scenarios. The acronyms are derived from the first word of each step, as shown below.

DMAIC:  This methodology is used to modify an existing business process and increase efficiency. It has five phases:

1. Define the objective of improving business process coherent with consumers’ demands and business strategies

2. Measure key factors of current process and gather relevant data-set

3. Analyze the data-set and find out the cause-and-effect relationship in the current process so as to detect causes of defects

4. Improve the current process and increase processing capability to the optimal level based on the analysis

5. Control key aspects of the business process before they result in defective output.

DMADV:  This methodology is used to design a new product or business process. It also has five stages:

1. Define the problem or objective consistent with business strategies

2. Measure the current process and collect relevant data to meet customer needs

3. Analyze data and determine the relationship between parameters and performance

4. Design a process that will satisfy customers' needs

5. Verify the new design so that performance is ensured and customers' needs are satisfied

Why Choose Six Sigma?

There are several reasons why Six Sigma has become so popular among manufacturing companies around the world. First and foremost is that detecting the main cause(s) of defects is quite easy and the analyses are conducted from pertinent data sets rather than mere assumptions. Due to this process, both productivity and quality of products can be increased, potentially leading to more sales and therefore profits. Secondary benefits include an increase in company value and increased employee and customer satisfaction.

Without a doubt, Six Sigma is a value-laden methodology that improves the productivity and performance of any manufacturing business. Its success as a business tool has led to its widespread proliferation into every industry and country.