Pdca

Evolution of the PDCA Cycle

Ronald Moen1, Clifford Norman2

1. Associates in Process Improvement-Detroit (USA), ronmoen@aol.com

2. Associates in Process Improvement-Austin (USA), cnorman@apiweb.org

Summary

The PDCA cycle had its origin with Dr. W. Edwards Deming’s lecture in Japan in 1950.

Where did he get these ideas and how have these ideas evolved since those lectures?

This presentation will move from the 1600’s with Galileo and the philosophy of science

through the evolution of the scientific method and the science of improvement. Walter

Shewhart in 1939 applied the scientific method with his cycle: specification-productioninspection.

W. Edwards Deming in 1950 modified the Shewhart cycle: design of the product,

make it, put it on the market, test it through market research, then redesign the product.”

The Japanese interpretation of the “Deming wheel” in Dr. Deming’s lectures of 1950 and

1951 lead to the plan-do-check-action or PDCA cycle. This cycle was integral to the Japanese

QC, TQC, and QC circle activities. Deming introduced his Shewhart cycle for learning and

improvement in the USA in 1986. Dr. Deming introduced a more abbreviated PDSA cycle in

1993.

In 1994, the PDSA cycle was accompanied by three questions to aid in the planning step

of the PDSA Cycle. In 1996 and 2009 publications, the PDSA cycle was broadened to

include strategies and methods to develop, test, and implement changes that would result in

improvement. This version was called the “Model for Improvement.” As an introduction to a

framework for improvement, the model for improvement has been found to support

improvement efforts in a full range from the very informal to the most complex.

Keywords

Scientific Method, W. Edwards Deming, PDCA, PDSA, Model for Improvement

1. Introduction to the Scientific Method (1600-1900)

When did the science of improvement begin? Juran [1] states that the origin of handicraft

industries and their quality control in China’s history can...