PDCA is a 4-step, iterative method commonly used for Business Process Improvement.  PDCA stands for Plan, Do, Check, Act.  It was popularized by Dr. W Edwards Deming in the 1950s during his work in Japan where he taught top management how to improve product design, quality, testing and sales. 

The process is originally attributed to Walter A. Shewhart and was referred to by Deming himself as the Shewhart Cycle.  The Shewhart Cycle steps were listed as Specification, Production, and Inspection.  However, over time, the steps were shortened to the more easily remembered Plan, Do, Check, Act (also referred to as PDSA—Plan, Do, Study, Act) where the Act step emphasized the need to take action on the knowledge gained from the prior step.

PDCA (or PDSA) is firmly rooted in the Scientific Method—Hypothesis, Experiment, Evaluation.  A fundamental principle of these methods is iteration.  Once the result of a process is confirmed (or negated) the cycle is repeated and the new knowledge can be acted upon.   It is this process of taking action, measuring the results, and utilizing those results to develop the next course of action that make the PDCA method and others like it, such as the Six Sigma DMAIC process (Define, Measure, Analyze, Improve and Control), so powerful and beneficial as a tool for the Business Analyst.

These methods, and others like them, which employ and iterative feedback loop embody two key points:

• Creating a feedback loop based on measurable results
• Making incremental changes and improvements over time