Ron Moen and Clifford Norman wrote a very interesting article on the history of the PDSA cycle: Clearing up myths about the Deming cycle and seeing how it keeps evolving.
It is not enough to determine that a change resulted in improvement during a particular test, according to Moen, Nolan and Provost. As you build your knowledge, you will need to be able to predict whether a change will result in improvement under the different conditions you will face in the future.
The experiment in the PDSA cycle is carried out to learn about the system in question. I like to call it the Do-the-experiment step to emphasize that doing in the PDSA cycle refers to “doing the experiment”. Otherwise people often forget that what we are doing is running an experiment to learn from. We want to find improvements. But we want to find improvements that are predictable and sustainable.
The inclusion of the 3 questions should be familiar to everyone who uses The Improvement Guide. And if you are not using that book, you should be. As I have mentioned before it is the best handbook for applying the PDSA cycle to improve results.
Those 3 questions will greatly aid your attempts to use the PDSA cycle in your organization.
Related: Deming 101: Theory of Knowledge and the PDSA Improvement and Learning Cycle – Tom Nolan at the Deming Institute Conference on PDSA (turn the cycle quickly) – Ron Moen Webcast: Prediction is the Problem – Keys to the Effective Use of the PDSA Improvement Cycle