Six Sigma – Metrics

Rick Lapenna Insights, Six Sigma Leave a Comment

In modern day scenario, it is very important to track down the simple metrics, manipulate and improve numbers. The concept of Six Sigma and other methodologies not only measures site activity but also strive to understand the factors affecting the metrics. Six Sigma is referred as a business-driven, multi-faceted approach, which focuses primarily on process improvement, reduced costs, and increased profits.

Common Six Sigma metrics include defect rate (parts per million or ppm), sigma level, processcapability indices, defects per unit, and yield. Many Six Sigma metrics can be mathematically related to the others.

Defect Rate

The complimentary measurement of yields is defects. If the yield is 90 percent, naturally there must be 10 percent defects.

Sigma Level

From a quality perspective, Six Sigma is defined as 3.4 defects per million opportunities. This is called a sigma level of quality.

Process Capability Indices

Another set of measures exist to quantify the capability of a process or characteristics to meet its specifications. These indices directly compare the voice of the process to the voice of the customer.

Defects Per Unit

DPU provides a measurement of the average number of defects on a single unit.


Traditionally, yield is the proportion of correct items you get out of a process compared to the number of raw items you put into it.

With the fundamental conviction and drive to improve customer satisfaction by reducing defects, the foremost aim of Six Sigma is to result in defect-free processes and products (3.4 or fewer defective parts per million (ppm). The process to achieve this goal consists of various steps in the Six Sigma methodology, including “Define – Measure – Analyze – Improve – Control”.

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