Back in 1986, Motorola Inc. originated “Six Sigma” as a way to reduce defects within their core manufacturing process and was later extended to other business areas in order to make improvements in broader operations of the company.
The term “Sigma” refers to a scale used to determine the levels of quality within a given process. Six Sigma equates to 3.4 defects per one million opportunities (DPMO). A Six Sigma defect is defined as anything that falls outside customer specifications, internal or external.
Today, there is less emphasis on the specific definition of the 3.4 DPMO where it is now more widely adopted as a general term to address overall business improvement methodology that concentrates on the following key points:
DMAIC is a step-by-step approach for improving existing business processes.
At the core of the Six Sigma methodology is the DMAIC (define, measure, analyze, improve, and control) model for existing processes where incremental improvement is required.