PDSA is a similar cycle to PDCA. Plan, Do Study, Act are the four elements of this cycle. The third step is Study rather than Check. While similar, they are not exactly the same. The use of Study instead of Check includes more in-depth review of the results from the Do stage. The PDSA grew out of the PDCA as Dr W. Edwards Deming focused on more detailed reflection of the data being studied. It's not just enough to check whether your plan worked. You need to measure it and document it.
PLAN - In the Plan stage, you plan out a course of action and predict what you expect to happen. There is a purpose behind the plan of action. You are hoping to accomplish something specific. Maybe you want to improve the quality of product coming from a specific device. Or maybe you want to reduce the amount of times spent between jobs on a specific device. So, you plan out what it will take to accomplish that and write down what you expect to happen. Let's say you want to improve a fold on a note card. The fold is pretty good, but it's not centered on the art perfectly. To formulate a plan you might say, "If we reduce the programmed trim size by 1/16th of an inch, hopefully the fold will be centered correctly." There's the plan, there's the prediction. Write it down and start to track your progress. Keep the plan simple. Make as few changes as possible. If you change multiple things at the same time, you might not be able to identify what change had what result. Aim small, miss small.
DO - In the Plan stage, you carry out the details of the plan. With the purpose of improving the fold on a note card, you execute your plan. You reduce the trim size in the folder program by 1/16th of an inch. You expect that with the slightly shorter trim size programmed, the fold will be placed in the center of the card. Once you have programmed the change in the folder, you run a few cards through to see where the fold is on the note card.
STUDY - In the Study stage, you compare your planned predictions to the result produced in the Do stage. In our example, you measure the score or fold on the note cards you ran through after making the adjustments in the folder program. You measure each side. You measure each note card. Is the fold exactly centered? If not, was the adjustment too much or too little? Is the fold consistent on the test note cards that you ran through after the change? If not, could the machine be in error and need its own troubleshooting and/or maintenance? Let's say the machine is producing consistent results and the fold on the note card needs to move back a little.
ACT - In the Act stage, you adapt, adopt, or abandon your plan. In our example, the plan needs to be adapted, as is usually the case. You determine from your study that the fold is the same distance from the center, but now on the other side of the art. So, you start over the PDSA cycle with a new plan to change the programming on the folder by negative 1/32th of an inch. This cycle is repeated until the fold is in the center.
The PDSA cycle is used unofficially all the time. You're probably recognizing it as something you've done or do frequently. In reality this is something you do regularly when you’re trying to trouble shoot any problem at work or at home. The difference is the documentation and the way this process interacts with other processes to improve an organization as a whole. Even in work situations, it is usually done without physical tracking overall progress of our organization and is limited to a localized process. The PDSA cycle is meant to be documented and used over and over until it can't be used on one process and then moved to another process, constantly improving. Just because a process was focused on and improved in the past doesn't mean it doesn't need improvement now or in the near future. Equipment changes, materials change, operators change, instructions change, and ultimately the process needs to be put through PDSA again until it is optimized again. And as the PDSA cycle is utilized it is to be documented. This documentations helps you keep track of all the pertinent details and strengthens accuracy. Documentation though serves a deeper purpose, it is built into the entire systems continuous improvement documentation that tracks all processes and coordinates their efforts for large scale improvement. Each PDSA cycle is a brick in the foundation of a growing and improving organization.
