PDCA was made popular by Dr. W. Edwards Deming, who is considered by many to be the father of modern quality control; however it was always referred to by him as the "Shewhart cycle." Later in Deming's career, he modified PDCA to "Plan, Do, Study, Act" (PDSA) so as to better describe his recommendations. The concept of PDCA is based on the scientific method, as developed from the work of Francis
... [Show full abstract] Bacon (Novum Organum, 1620). The scientific method can be written as "hypothesis" - "experiment" - "evaluation" or plan, do, and check. Shewhart described manufacture under "control" - under statistical control - as a three step process of specification, production, and inspection.[1] He also specifically related this to the scientific method of hypothesis, experiment, and evaluation. Shewhart[2] says that the statistician "must help to change the demand [for goods] by showing...how to close up the tolerance range and to improve the quality of goods." Clearly, Shewhart intended the analyst to take action based on the conclusions of the evaluation. According to Deming[3] during his lectures in Japan in the early 1950's the Japanese participants shortened the steps to the now traditional plan, do, check, act. Deming preferred plan, do, study, act because "study" has connotations in English closer to Shewhart's intent than "check." A fundamental principle of the scientific method and PDSA is iteration - once a hypothesis is confirmed (or negated), executing the cycle again will extend the knowledge further. Repeating the PDSA cycle can bring us closer to the goal, usually a perfect operation and output.