PDCA concept: The Process Improvement Cycle Explained

The PDCA concept usually refers to the famous administrator who popularized it: William E. Deming. But in fact, the PDCA concept (or cycle) emerged in the 1930s, designed by American Walter Andrew Shewhart. Deming was responsible for its widespread circulation which eventually got the concept to Japan where it was applied in businesses there.

The Definition of PDCA

  • Plan
  • Do
  • Check
  • Act

It is often referred to as a cycle. It means that continuous improvement is at work each time the cycle is activated and returns to its beginning.

View more: Understand what the Kaizen Continuous Improvement Process is and how to apply it to the improvement and quality management of your company

The PDCA Concept

The basis of this tool is the repetition. It is applied successively to the processes that seek to improve continuously. In this context, planning, standardization, and documentation are essential practices and accurate measurements. Other factors addressed by the PDCA concept are the talents and skills of the professionals involved.

But how can we define in a summarized and didactic way what is the PDCA cycle? Here it goes:

The meaning of PDCA:

PDCA is an acronym that gives name to a tool used in process quality management. Its focus is to solve problems by following the four phases indicated by its letters: Plan, Do, Check and Act. Because it’s a cyclical tool, it also promotes continuous process improvement.

See also: 3 Tools for Quality Management and Processes

The 4 stages of the PDCA Concept Cycle


It is the stage where we analyze the problems that we want to be solved, according to the following order:

  • Definition of problems
  • Setting goals
  • Choice of methods
  • Ask the question five times: why did the problem occur? Always making a complete answer.

Here, the PDCA concept is beginning to show: a structured and organized repetition to find solutions.

The 5 Whys and the PDCA Process

There is no way to plan a solution to a problem without identifying its root cause, the root problem, the one that really is the initial reason for everything.

For example, imagine that you discover a problem in your home: the light is not turning on in a certain room.

You might ask:

Why doesn’t the light come on? The answer is obvious, the bulb must have blown.

You check the bulb and find out that it really has blown, but;

Why did the bulb blow?

When checking the fuse box, you discover that the circuit breaker for that room is off.  You conclude that when this happened, the light blew before the circuit breaker switched off.

You could just turn it back on, but ask yourself;

Why was the circuit breaker off?

Usually this happens because of a power surge over the capacity of the circuit breaker.

But Why was there such an overload of energy?

You go back to the room and notice that there are several devices connected to one outlet, through an adapter, which generated an overload in that circuit.

But Why put so many devices in the same outlet?

Finally, you discover that another outlet in that room, formerly used to connect items to the power grid, is blocked by a change in the layout of the furniture.

At the beginning of this conversation, if someone had said that the light in the room was off because someone had changed the location of the furniture, would you consider that an appropriate response? Possibly not, and so, this is why the 5 Whys method is so widely used.

Look at the sequence of “whys” you asked until you discovered the real cause of the problem you wanted to solve:

  1. Why doesn’t the light come on?
  2. And, Why did the bulb blow?
  3. Why was the circuit breaker off?
  4. Why was there such an overload of energy?
  5. But, Why put so many devices in the same outlet?

See more details on our blog: The method of 5 whys in search of quality


It’s time to get hands-on, executing what was determined in the previous step:

  • Practice the method
  • Execute
  • Make changes
  • Don’t need to strive for perfection, just look for what can be done in a practical way
  • Measure and record the results

It’s interesting to note that at this stage of the PDCA model, despite being called DO, you don’t actually begin doing anything that will solve the problem, you’re only empowering the people who will have to act, who roll up their sleeves and put things into practice.

Without proper training, the execution of the PDCA cycle will certainly be compromised.

There is a phrase attributed to American President Abraham Lincoln that illustrates this situation well, where preparation is as important as action:

pdca concept

Source: Imgur

Another important point in the DO phase of the PDCA process is not looking for perfection, only what can be achieved in a practical way. Like any good statistician, Deming knew that by reaching a certain level of excellence, going beyond him in pursuit of perfection could outweigh any small problems.

So stay tuned and don’t overdo it in your quest for unattainable quality. Define standards that can be reached and measure whether the variance is within acceptable limits.


It is one of the most important steps that define the PDCA concept cycle. After checking, we will see if the action has improved:

  • Check whether the standard is being obeyed
  • Check what’s working and what’s going wrong
  • At every step, ask why?
  • With the answers, improve and practice the defined method

Can the Ishikawa diagram help with the PDCA model?

In fact, in the same way as the 5 whys, the Ishikawa diagram, also known as fishbone, can help both in the planning phase, when the problem is discovered, and in the checking phase.

Also: the method of the 5 whys is used in conjunction with the Ishikawa diagram, as you will see below.

Check out this diagram of the Ishikawa method before continuing to read:

Source: Auxilus

Ishikawa determined 6 possible problems, which must be investigated with the help of the 5 whys method:

  1. Method: the method used may be the cause of the problem. You need to check that it’s the right one.
  2. Material: poor quality, defective, inappropriate or outside of the necessary specifications.
  3. Labor: selection, quantity, training, motivation at work, qualification, among other factors, should be analyzed.
  4. Machines: Is the equipment up to date? Are the machines working properly? Are they properly regulated? Is maintenance up to date?
  5. Measures: Are the metrics chosen effective in controlling the expected results? Are the measuring instruments calibrated and reliable? Is the way to calculate the metrics simple and easy to apply?
  6. Environment: Is the work environment adequate? Is it adequately protected from the elements, sounds, gases and other elements?

By carefully analyzing each of these points, it will be possible to make the working method that solves the problem even more assertive and efficient.


Time to act more assertively.

  • Things going as planned? Then continue!
  • Well actually, there are some problems? Then act to correct and prevent the errors!
  • Improve the work system
  • Repeat the solutions that worked

At the end of the fourth phase, the PDCA concept suggests that the cycle restarts again, to seek a continuous and uninterrupted improvement.

When the method has been defined and begins to be applied, the measurements must be even more intense, in search of errors and deviations. If nonconformities are found, the PDCA process restarts, in search of continuous process improvement.

If you want to know even more about the PDCA model, check out Deming’s 14 points:

Warnings when applying the PDCA concept

  • Only proceed to the DO phase after having considered the PLAN phase
  • If you find that during the ACT stage there is an excess of repetitions and attempts, return to the PLAN phase
  • Avoid a short circuit in the cycle, by not skipping stages or not devoting enough time for questions and searching for the “whys”.

Process Management Life Cycle

PDCA is a very comprehensive and applicable approach in many situations, but sometimes we need to create specializations to help solve specific problems. See in this video how PDCA can assist in managing business processes.

Check also: Find out what project management processes are in detail and understand their functions, here.

The PDCA concept in conjunction with BPM systems is a powerful combination for the analysis and management of processes.

The PDCA concept is simple but laborious

Many delude themselves when using the PDCA concept believing it to be a tool that doesn’t require dedicated and meticulous work. Within the most common mistakes we can highlight:

  • Lack of reasoning when responding to the “whys”
  • Analysis of incomplete scenarios
  • Inefficient training
  • Incomplete records
  • Inaccurate measurements
  • Insufficiently detailed standardization

See also:

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