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PDSA: A Scientific Approach to Continuous Improvement

Posted by Greg Jacobson

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Mar 23, 2015 7:26:00 AM

PDSACycleDr. W. Edwards Deming is considered by many to be the father of modern quality improvement. Among other important insights into how businesses could become more efficient, reduce costs and increase customer value, he popularized Plan-Do-Study-Adjust (PDSA), a four-step cycle used to achieve continuous improvement in processes and products.

The PDSA approach, sometimes called the Deming Cycle, is based on the scientific method, which approaches problems through hypothesis (plan), experimentation (do) and evaluation (study). In business, the output of a successful PDSA cycle is a new standard that institutionalizes the improvement. The cycle can begin again and further improvement can be achieved.


The planning step must include answers to the following questions:

  • What are we trying to accomplish?
  • Do we really understand the problem and the current situation?
  • How will we know if the change is an improvement?
  • What changes can we make that will result in improvement?

During the planning phase, it is important to not jump to solutions, as people so often tend to do. It's often said that half of the time in a PDSA improvement cycle is spent on "plan," even if it's illustrated as four quadrants of a circle. 

The plan should identify the individuals who will be involved in testing the improvement and those who will be impacted by it. A time line should be determined and a communication plan developed.



Once the planning phase is complete and a hypothesis has been made about specific changes that are expected to lead to measurable improvement, the “do” step can begin. This part of the cycle should be considered experimental. As with a scientific experiment, careful observation and data collection is just as important as the action itself. We don't want to jump to the conclusion that our action is really an improvement.



The study step is arguably the most important of the PDSA cycle. During this phase, the actual results of the experimental improvement are compared against the expected results. The reality of the implementation is compared against the plan to make sure that what was done matches what was proposed and to make sure that there weren't any side effects created by the change. The data gathered is analyzed to determine if a measurable improvement was achieved and if it meets the expectations defined in the planning phase.



Only if the study phase reveals that the change was implemented as expected and resulted in the anticipated improvement (without causing any new problems), does the adjust step begin. If the conditions are met, the changed process becomes the new baseline for future activities. Standard work documents are adjusted to include the change and performance expectations are modified accordingly.  The cycle is then repeated against the new process and additional improvements can be achieved.


As visually represented here, the PDSA approach can be used to identify new standards that result in constantly improving process quality and, therefore, customer value. The guesswork is removed from improvement initiatives, making it easy for organizations to quickly realize the benefits.

What's the ROI of continuous improvement using methods like PDSA?

The ROI of Improvement


Topics: Change Management

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