The PDCA cycle was in fact originally developed by Walter A, Shewhart, a Bell Laboratories scientist who was Deming's friend and mentor, and the developer of Statistical Process Control (SPC) in the late 1920s.
Many quality practitioners believed that the check stage of the process meant to simply measure the improvement and move forward to the Act stage. Deming was stressing the importance of studying the data collected prior to acting upon it by changing the name of the stage to study.
DO the planned activity. ... This is the implementation stage during which the plan is actually tried out in the operation. The people responsible need to be trained and equipped with the resources necessary to complete the task. This stage itself may involve a mini PDCA cycle as the problems of implementation are discovered and resolved and we begin to see if the implementation of the plan is providing results.
Plan to improve your operations first by finding out what things are going wrong (that is identify the problems faced), and come up with ideas for solving these problems.
Act - depending upon the results from the prior step, standardize and stabilize the improvements to sustain them or begin the cycle again.
Recently, some have renamed the fourth step as "adjust" to bette reflect the step's spirit of continuous improvement.
The Deming Cycle approaches often do not get to the root cause of a problem, especially in adaptive situations which call for an experiential approach but demand much more rigour in analysis and data collection. An adaptive challenge exists where there are no visible solutions to problems, and can exist, for example in areas where chaos, uncertainty, and ambiguity exists, such as new frontiers, and existing complex systems such as Healthcare.
Usually the focus of the process is on internal management control: it does not take external factors such as change in markets into account. We plan, execute, analyze the outcome, and see how we need to adjust our actions based on the outcomes so far.
W. Edwards Deming in the 1950's proposed that business processes should be analyzed and measured to identify sources of variations that cause products to deviate from customer requirements. He recommended that business processes be placed in a continuous feedback loop so that managers can identify and change the parts of the process that need improvements. As a teacher, Deming created a (rather oversimplified) diagram to illustrate this continuous process, commonly known as the PDCA cycle for Plan, Do, Check, Act
PDCA cycle is sometimes referred to as (1) the Shewhart cycle because Walter A. Shewhart discussed the concept in his book entitled Statistical Method from the Viewpoint of Quality Control or (2) the Deming cycle because W. Edwards Deming introduced the concept in Japan; the Japanese subsequently called it the Deming cycle. It is also called the Plan-Do-Study-Act (PDSA) cycle.
The recurrent cycle of four steps is the foundation for any continuous improvement effort and is based on the scientific method for logically proving or disproving a theory. Simple to construct and use, the plan, do, check, adjust cycle makes evaluating an organizational or personal improvement an easy, straightforward, and perfectly provable task for adults, students, or teams.
The Plan-Do-Check-Adjust (PDCA) cycle is W. Edwards Deming's gift to the world. No mental model is more important - and more misunderstood. PDCA is an expression of the scientific method to which our society owes its prosperity. It's also the foundation of strategy deployment.