Guest Post – Words Matter: Why I Prefer PDSA over PDCA
Mark's note — today's guest post is by my friend Karen Martin, my guest for Podcast #151 where we talked about her latest book The Outstanding Organization: Generate Business Results by Eliminating Chaos and Building the Foundation for Everyday Excellence. Karen is the founder of Karen Martin & Associates and she is also the co-author of The Kaizen Event Planner: Achieving Rapid Improvement in Office, Service, and Technical Environments and Metrics-Based Process Mapping: Identifying and Eliminating Waste in Office and Service Processes
Think you know where PDCA (plan-do-check-act) came from? Think again. As I was writing my book, The Outstanding Organization, I dug into this powerful approach for problem solving and was surprised by what I learned.*
The two most influential voices for fact-based management in business have been Walter Shewhart, who is often referred to as the “father of statistical quality control,” and W. Edwards Deming, the “father of the Total Quality Management movement.” In the late 1930s, Shewhart converted the traditional view of mass production as a linear, three-part model involving specification, production, and inspection into a continuous-feedback quality control loop that relied on the scientific method of forming a hypothesis, carrying out an experiment, and proving or disproving the hypothesis. As Shewhart's editor, Deming helped Shewhart simplify his concepts for publication. Deming continued to modify Shewhart's cycle and in 1950 presented the concept at a lecture to the Japanese Union of Scientists and Engineers (JUSE). The cycle became known as the Deming Wheel: design, production (make), sales (sell), research (redesign through market research). Testing was implicit in all four steps of the cycle.
According to Masaaki Imai, who is often referred to as the “father of kaizen,” an unnamed group of Japanese executives recast the Deming wheel into the PDCA cycleâ€”plan, do, check, actâ€”a four-step cycle for improvement.
Kaoru Ishikawa contributed several key subcomponents to the PDCA cycle, notably, that the plan phase includes setting clear goals and targets, the do phase includes significant training and education during the implementation of any improvement, and the check phase includes continuous revision of standards in response to the voice of the customer and changing requirements of the next step in the process. Through Ishikawa's influence, PDCA began being viewed as a significant management tool and the standard for making continuous improvements to processes and systems.
In the 1980s, Deming expressed his view that owing to translation difficulties from Japanese to English, the PDCA cycle had been corrupted. Deming recommended replacing PDCA with PDSAâ€”plan, do, study, adjustâ€”which he felt was linguistically closer to Shewhart's original intent. Deming continued to refer to the cycle as PDSA through the 1990s and dubbed it the Shewhart Cycle for Learning and Improvement.
I'm with Deming. Over the more than 20 years that I've been involved in quality improvement, operations design, and problem solving, I've found that the words check and act in PDCA mask the intent of those steps, which are to study the results of one's experiment and then make adjustments based on the results from the countermeasure(s) put in place to test the hypothesis. People often mistake check for making sure that everyone is following the new process rather than checking the results of the experiment and adjusting the countermeasures accordingly. In addition, people often act without adequate reflection and adjustment.
I still sometimes slip and use PDCAâ€”it's been habituated in my brain and vocabulary for over 20 years. But I'm committed to helping people become proficient problem solvers as quickly as possible, and I've found using “study” and “adjust” helps quite a bit on this front. So PDSA it is.
*While there are many accounts about who developed what, in what sequence, and when, the most complete and well-documented account I've found is a white paper, Evolution of the PDCA Cycle, by Ronald Moen and Clifford Norman. In it, the authors present a view about Dr. Deming's role in the development of the PDCA cycle that varies from popular folklore.