A Different View of the Funnel Experiment

Deming's funnel experiment has been used to illustrate the principle, that, in some situations, by actively controlling a process the variance of the process output will be increased. Although this is true in certain situations, these situations do not often occur in the continuous process industries where active process control has been applied with excellent results for decades. This note analyzes these situations, and illustrates the improvements possible through active control to a target.