Walter ShewhartEconomic Control of Quality, 1931
Distinguish common-cause variation (inherent to the system) from special-cause variation (assignable events) using control charts — and only act on the difference.
W. Edwards DemingOut of the Crisis, 1986
Tampering with a stable system makes it worse; management's job is to improve the system, not react to every point that wiggles.
The EclipseFrontiers® LensNot every wiggle is a signal. Charts keep managers honest.