What is PDCA or Plan-Do-Check-Act?

Guest Blog from Acuity...

PDCA (Plan-Do-Check-Act) is a four-step management tool used to implement, manage, and drive continuous improvement. It is also a key part of lean manufacturing.


Walter Andrew Shewhart Ph.D., a data scientist at Bell Laboratories, is credited with developing the PDCA model in the 1920s. As such, PDCA is sometimes referred to as the Shewhart Cycle. Shewhart was also the mastermind behind SPC (statistical process control). W. Edward Deming Ph.D. popularized PDCA. He saw it as a great tool for quality improvement and made it a key tool in the lean toolbox.


PDCA can help drive a company’s culture and mindset of continuous improvement, problem solving, and accountability. It can assist in eliminating problems, improving performance, reducing waste, better controlling expenditures, increasing OEE, improving safety, and more.


PDCA is a cycle that keeps driving improvement. You never stop—solve a problem, improve an issue, and repeat.


Here are some tips for implementing PDCA in your business:



Identify what is wrong, analyze the problem, and develop a solution. Make sure the problem you identified is the right problem that needs to be addressed. Use data and facts. Without data, how do you know the status of the problem and whether you have improved or solved the issue? This doesn’t mean you can’t PDCA a process that is meeting your expectations. Even good processes often have room for improvement.



Develop and implement a solution. Before implementing your solution, make sure you have decided what the goal is and how to measure progress. There are a variety of problem-solving tools, such as the fishbone cause-and-effect diagram, the 5 whys, and brainstorming, that can help with this. Pareto charts, KPI information, SPC, or any other reliable information that is tracked or monitored can be used.



Verify your results as you test and implement solutions. A key here is to continually monitor how your solution is performing in the long-term. Remember, you might want to revisit and attempt to improve even more or use the solution for similar issues elsewhere. Review and analyze the results to see if you can do better or if you have achieved the desired improvement.



Document your results as well as the changes you have made. You want to remember what was done in case a similar issue arises elsewhere or your solution causes problems later. You can use that information to get back to ground zero or as training materials for other teams. Nothing is better than showing others within your company how PDCA helped solve an issue or improve a process in the company.


A few hints and tips:

  • PDCA works best in a team environment. More people bring more ideas, insight, and information. It also helps to share the workload, since we all have a full-time job to do.
  • As you develop potential solutions, also develop a testing and verification plan.
  • If you have an environment where you continually collect and analyze data, you can use it to identify areas for improvement. This data can be the trigger for when and where to use PDCA.



You have an operation that runs three eight-hour shifts. Every morning at 7 a.m., you and your team review the data and ask questions about any item that did not meet the established KPIs or measurements. Then, decide if it is a one-time fluke or an ongoing issue. Let’s say output was low over the last 24 hours. You know three employees called in sick during the last 24 hours. You could decide to document and monitor this. If you see the same issue multiple times per week or in a work cell, you might have a good candidate for a PDCA. You might ask, "Why do we have more call-ins in work cell A?"


Michael S.

Manufacturing Expert with Acuity

Republished from "focus" blog by Acuity, with approval of author.

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