PDCA (plan–do–check–act) is an iterative four-step management method used in business for the control and continual improvement of processes and products.

It is also known as the Deming circle, the Shewhart cycle or plan–do–study–act (PDSA)


PDCA Kaizen


A fundamental principle of the scientific method and PDCA is iteration—once a hypothesis is confirmed (or negated), executing the cycle again will extend the knowledge further. Repeating the PDCA cycle can bring its users closer to the goal, usually a perfect operation and output (or “True North”)

Another fundamental function of PDCA is the separation of each phase, for if not properly separated measurements of effects due to various simultaneous actions (causes) risk becoming confounded.


PDCA is also known as a system for developing critical thinking. At Toyota this is also known as “Building people before building cars”. Toyota and other lean manufacturing companies propose that an engaged, problem-solving workforce using PDCA in a culture of critical thinking is better able to innovate and stay ahead of the competition through rigorous problem solving and the subsequent innovations (see book The Toyota Way)

PDCA explained

Plan: Define the problem to be addressed, collect relevant data, and ascertain the problem’s root cause.

Do: Develop and implement a solution; decide upon a measurement to gauge its effectiveness.

Check: Confirm the results through before-and-after data comparison.

Act: Document the results, inform others about process changes, and make recommendations for the problem to be addressed in the next PDCA cycle.


PDCA steps and checklist

1 Define the Problem

What is the problem (avoid solutions)
Team complete
VOC and Value clear
Learn from previous improvement actions


2 Collect the facts

On the work floor itself, see what the problem is (gembo)
Measuring the facts
Sketch the process (Value Stream Map)


3 Analyze the facts

Analyze the facts and come to the core (“root cause”), eg by 5xWhy orFishbone diagram


4 Generate solutions

Generate solutions eg via a brainstorming session
Choose the solution


5 Implement

Make a plan and schedule, for example via an A3 form. Request agreement.
Realize and implement

6 Checking and Act

Check whether the problem has been removed and no longer returns. Act in case of inaccuracies
Provide standards
Learn and evaluate
Celebrate success.

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