What is the PDSA Cycle? Download the Shewhart Cycle PDF
The PDSA Cycle, also known as the Shewhart Cycle, was originally developed by Walter Shewart. Dr. W. Edwards Deming adopted and implemented the PDSA Cycle into his continuous improvement methodologies. In short, the PDSA Cycle is a flow diagram model for learning and for the improvement of a process or product. PDSA simply stands for Plan Do Study Act. The Shewhart Cycle for learning & improvement is straight forward. Sadly, many businesses ignore or short circuit this process inevitably ending in failure, lost time, profit loss, and backtracking. Let’s take a closer look.
PDSA Cycle: An In Depth Look
PLAN: Someone has an idea for improving a process or product. This phase is also known as the 0-th stage. Step 1 is the foundation of the whole cycle. A hasty start may be ineffective, costly, and frustrating. People have a weakness to short-circuit this step. They cannot wait to get into motion, to be active, to look busy, to move into Step 2.
The planning stage may begin with a choice between several suggestions. Which one can we test? What may be the result? Compare the possible outcomes of the possible choices. Of the several ideas, which one appears to be most promising in terms of new knowledge or profit? The problem may be how to achieve a feasible goal.
DO: Carry out the test, comparison, or experiment, preferably on a small scale, according to the layout decided in Step 1.
STUDY: Study the results. Do they correspond with hopes and expectations? If not, what went wrong? Maybe we tricked ourselves in the first place, and should make a fresh start.
ACT: Adopt the change.
or Abandon it.
or Run through the cycle again, possibly under different environmental
conditions, different materials, different people, different rules.
The reader may note that to adopt the change, or to abandon it, requires prediction.
As you can see the PDSA Cycle is simple to understand. The Shewhart Cycle is a fundamental roadmap for continuous improvement. It can be universally applied in the improvement of products, manufacturing processes, business practices, and dare I say, even in government/civic endeavors. Please note that this post is derived from W. Edwards Deming, The New Economics for Industry, Government, Education (Cambridge, MA: Massachusetts Institute of Technology, Center for Advanced Educational Services, 1993), pp. 134-136. I redesigned/upgraded the graphic for the PDSA Cycle using color to accent the cycle’s underlying meaning. Over the years, I have found that color adds an additional dimension aiding in the reader’s retention, reference, and memory.