Six Sigma

Six Sigma is frequently associated with the Lean Management concept. The Greek letter "Sigma" refers to the notion of variability and standard deviation. Its fundamental principle is to improve customer satisfaction by reducing variability.


Initiated by the American company Motorola in the 1980s to improve performance, Six Sigma has evolved from a strictly operational and statistical analysis of production gaps to a global and strategic approach based on improving customer satisfaction.


The Six Sigma method is based on the observation that customer dissatisfaction is the result of a gap between the expected situation and the actual situation. All processes are subject to these variability constraints such as the quality of components or the proper application of procedures. The strategy therefore is one of continuously combating these impacts by setting up management indicators in order to reduce manufacturing defects.


Lean Six Sigma


The Six Sigma method and Lean Management have generated a global approach called Lean Six Sigma. Indeed, while the Six Sigma method helps to eliminate defects and hazards while reinforcing the reliability of processes, it does not meet the challenges of flow optimization. Lean Management, on the other hand, reduces complexity and promotes faster yields, but does not address process reliability. The combination of these two approaches is part of a Continuous Improvement methodology and constitutes an overall strategy to improve customer satisfaction.

Related definitions

Continuous Improvement Process | Kaizen Lean Management Constraints-based Optimization