Tag: common cause

Not all variation is created equal. Planned variation, like that in an experiment, is a process improvement strategy. Unplanned variation, however, is nearly always bad. Two types of variation concern a Six Sigma team: Common cause variation – All processes have common cause variation. This variation, also known as noise, is a normal part of […]

Practitioners often give priority to addressing special cause variation in their processes. But it can be profitable to pay closer attention to the predictable variation stemming from common causes.