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The History and Evolution of the PDSA Cycle

Posted by Maggie Millard

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Sep 15, 2015 1:57:27 PM

deming_quoteThe PDSA cycle of improvement is popular because of its simultaneous simplicity and effectiveness. It can be applied to a limitless number of processes across almost every industry. We thought it was worth a quick look back at how it came to be and how it has changed over time.

Dr. W. Edwards Deming

Deming was an American engineer, statistician, and management consultant. He started his career as an electrical engineer, later specializing in mathematical physics. He is best known for his work in the Japanese auto industry after WWII. He is considered to be the most influential non-Japanese person in the field of Japanese manufacturing. He championed the management principle of statistical process control, a precursor of Total Quality Management. It is not unusual for him to be credited with the rapid post-war economic rise of the Japanese economy.


The Shewhart Cycle

Deming was influenced by Walter Andrew Shewhart, an American physicist, engineer and statistician. Shewhart’s Statistical Method from the Viewpoint of Quality Control, published in 1939, first introduced the concept of a straight-line, three-step scientific process of specification, production, and inspection.

He wrote, “It may be helpful to think of the three steps in the mass production process as steps in the scientific method. In this sense, specification, production, and inspection correspond to hypothesizing, carrying out an experiment and testing the hypothesis, respectively. These three steps constitute a dynamic scientific process of acquiring knowledge.” He eventually clarified that the steps should go in a circle, rather than a straight line, and that concept became what is known as the Shewhart Cycle.


The Deming Wheel

Deming built off of Shewhart’s Cycle and modified it. In his new version of the Cycle, debuted in 1950, he stressed the importance of constant interaction among the four steps of design, production, sales, and research. This came to be known as the Deming Wheel or Deming’s Circle.




Although it is somewhat unclear who made the changes or why, at some point the Japanese executives modified Deming’s wheel into; Plan, Do, Check, Act (PDCA). This four step cycle for problem solving includes planning (a problem definition and a hypothesis about possible causes and solutions), doing (implementing), checking (measuring the results), and action (standardization if the results are satisfactory).



Deming was never fond of the PDCA cycle, noting that “check” in English is equated with “hold back.” In 1993 he introduced his new revision of the Shewhart cycle; Plan, Do, Study, Act (PDSA).




Deming died in 1993, but his work lives on. Today, the PDSA approach is used by businesses across the globe to solve problems, improve quality and enhance products. It’s a valuable tool brought to us by some of the world’s best thinkers in the science of process control and continuous improvement.

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Topics: Daily Improvement, Lean

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