Quality Improvement Methodology (continued)

Testing a Hypothesis

The scientific method generally involves planning a test, conducting the test, and studying the results. Quality management has adapted this method, expanding it by adding "act on what is learned." Thus, the expanded method includes plan, do, study, and act (PDSA), also referred to as Shewhart's Cycle for Learning and Improvement.² PDSA is a four-step process included in the testing and implementation stage of every QI method. The PDSA cycle is represented in Figure 2.

² W. Shewhart. 1934. The Economic Control of Quality of Manufactured Products. New York: D. Van Nostrand. (Reprinted by the American Society of Quality Control, 1980).