The Deming cycle or PDCA is a model for continuous improvement of quality. PDCA is an iterative four-step problem-solving process typically used in business process improvement. It consists of a logical sequence of 4 repetitive steps for continuous improvement :
Establish the objectives and processes necessary to deliver results in accordance with the expected output. By making the expected output the focus, the completeness and accuracy of the specification is also part of the improvement.
Implement the new processes
Measure the new processes and compare the results against the expected results to ascertain any differences.
Analyse the differences to determine their cause. Each will be part of either one or more of the PDCA steps. Determine where to apply changes that will include improvement. When a pass through these four steps does not result in the need to improve, refine the scope to which PDCA is applied until there is a plan that involves improvement.
PDCA was made popular by Dr. W. Edwards Deming, who is considered by many to be the father of modern quality control. In Six Sigma programs, the PDSA cycle is called "define, measure, analyze, improve, control" (DMAIC).