Nelson rules - Wikipedia

Nelson rules are a method in process control of determining whether some measured variable is out of control (unpredictable versus consistent). Rules for detecting "out-of-control" or non-random conditions were first postulated by Walter A. Shewhart[1] in the 1920s. The Nelson rules were first published in the October 1984 issue of the Journal of Quality Technology in an article by Lloyd S Nelson.

[TaKUMA]

“Nelson rules are a method in process control of determining if some measured variable is out of control (unpredictable versus consistent).”