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The PDCA (Plan, Do, Check, Act) is a basic tool for continuous improvement. More than a tool, it’s a philosophy.


Contrary to the vision of the Fordist model aiming to produce to the maximum of the capacity (“ you can have a car of any color as long as it is black !”), Shewart highlighted 2 concepts:

  • The first is to take into account the concept of customer satisfaction.
  • The second: Taking into account that design is an endless cyclic process.


Contrary to the vision of the Fordist model aiming to produce to the maximum of the capacity (“ you can have a car of any color as long as it is black !”), Shewart highlighted 2 concepts:

  • The first is to take into account the concept of customer satisfaction.
  • The second: Taking into account that design is an endless cyclic process.

Thus, he developed in 1931 a first ” wheel ” in 4 stages2 :

  1. Plan: develop a plan for change, collect baseline data, educate and communicate.
  2. do: Test the change, collect data from the process that is being changed.
  3. Study: compare with the reference data and analyze the results.
  4. Act: summarize and communicate, redo a cycle if the change is not satisfactory, follow the change over time, consider implementing the change throughout the system.


It was W. E. Deming who deployed the method. Building on the work of Shewart, he developed the wheel of ” Deming “, also known as the PDCA Wheel, in 4 stages: Plan, Do, Check and ACT. In 1938, Deming presented the PDCA cycle to American companies without the presence of Top Management. The method had no echo or membership.

It will be in July 1950 that he met the accession to Japan3. Sent to Tokyo in 1947 by the Allied forces staff, he had the opportunity to meet the executives close to the Keidanren (Japanese employers) who invited him to lecture and lecture on the subject. It thus convinces the companies of the interest to set up the PDCA. He holds this speech:

« Today, the products you manufacture are considered junk. If you listen and do what I tell you, in five years you will be opposed to customs barriers, and the standard of living in Japan is going to match that of the most prosperous countries ».

This will mark a break in the way of thinking of the companies and the setting up of the PDCA starts. This way of seeing the cyclical process is a real paradigm shift.

A “variant” of the PDCA:

Please Don’t Change Anything

About the PDCA:

“When the new standards are in place and the workers comply with them in the performance of their tasks, without anomaly, the process is mastered. The next step is, starting from a new state of affairs, to improve the standards to reach a higher level. »-Masaaki IMAI

About the SDCA :

“When things go wrong at Gemba, whether they record production releases or customer dissatisfaction, it is up to the framework to look for the root causes, take steps to remedy the situation and ultimately change the procedure of Work to avoid the recurrence of the same problem. »-Masaaki IMAI

The principle

In the philosophy of DEMING, understanding the sources and effects of variations, knowledge and psychology are the most important concepts4 It gathers under the phrase ” create consistency in improvement 5 .

In principle, the 4 steps represent6 :

  • Plan: To establish the objectives and the process necessary to deliver the results according to expectations. What transformation do we need? Do we have the data to make a decision?
  • Do: Implement the process. If there is a doubt about the effects, start at a smaller scale.
  • Check: Measure and evaluate the new process with respect to the objectives and postpone the results
  • Act: Make the point on all the steps and modify the process to improve it before its next implementation. Apply the necessary actions.

Details of the steps of the PDCA

Beyond a generic approach, PDCA is used to design a new product, improve an existing product, implement change (PDCA) or solve a problem (PDCA).

Step 1: Plan

Problem solving

Project Management

1. Describe the problem *: formalisation via the 5W2H and measure the current situation with indicators.

2. Implement the Conservatory actions: Implement temporary solutions (control 100%…) to continue to produce while guaranteeing customer quality.

3. Set up the project: define the multidisciplinary team, train it and put in place the key indicators for measuring the results achieved.

4. Look for root causes and prioritize them: Ishikawa and 5 Why to list all possible causes, then FTA… to identify the real cause.

5. Define the solutions to be made to solve the problem. Use the methods of analysis to choose the best solution (Pugh, Analysis of Decisions, AHP, Pairwise analysis).

6. Define the actions to be carried out to implement the chosen solution.

1. Define Project Objectives* *

2. Describe the context and the starting situation of the project.

3. Collect client expectations and prioritize them. We can use the classification of Kano Like what.

4. Build the action plan according to the expectations and resources available.

5. Define the project team and the schedule.

6. Set up the project monitoring and validation indicators.

*A well-posed problem is already half solved“-A. Einstein.

* * It is always best to cut a “big” project into several sub-projects. More easily “manageable”, they will allow to generate more gradually profitability and gradually improve the cash flow.

This strategy also helps to limit the failures of projects that do not end and to keep a better dynamic of improvements.

Step 2: Do

Problem solving

Project Management

1. Implement the chosen solution.

2. Inform and train staff on the solution and the provisional standards.

3. Apply the solution for a significant period of time.

1. Carry out the action plan defined above.

2. Regularly monitor the project to validate the progress of the actions.

At this point it is possible to make return trips to identify the right solution. This phenomenon is oversimplify by the fact that the do phase can be formed by a multitude of small PDCA.

Source: Y. Kondo (1995) – Company wide Quality Control

Step 3: Check

Problem solving

Project Management

1. Measure the results of the solutions on and check the “Gap“.

2. Compare the results to the initial situation (Hypothesis Testing).

3. Analyse the potential effects on upstream and downstream processes and the effects on future projects already planned.

1. Measure the results with regarding the starting indicators.

2. Improve solutions to bridge the gap between objectives and situation or because new opportunities have arisen.

3. Carry out a project review to assess the initial regarding objectives.

Step 4: ACT

This step should help to perpetuate the actions:

  • For problem solving: it should no longer reappear
  • For project Management: Closing the project by returning experiences

Problem solving

Project Management

1. Formalise solutions and implement solutions if possible to avoid recurrence: Poka Yoké, lesson in 1 point, standardization

2. Train staff to the new standards.

3. Valuing the Working group and the people who have implemented the actions.

4. Standardize the improvement on other similar products or processes (Yokoten).

1. Deploy the solution from the “Prototype” to the real and concrete realization phase: industrialisation, preseries…

2. Take the time to step back regarding the project to improve the process.

3. Take an update on other possible developments following the latter (Yokoten).


The control of the improvement leads to a succession of cycle SDCA /PDCA. When a good solution has been found, it is necessary to make it a ” standard ” in order to stabilise the process, reduce variability and meet the expected specifications.

The 4 steps of the SDCA 7 :

  1. Standardize: analyze the process to standardize, set the standard and formalize it
  2. do: inform, prepare and train, and enforce the standard
  3. Check: measure results, analyze and correct variances
  4. Act: prevent recurrences, finalize the standard, deploy standards

Generally, the SDCA is used under the following conditions:

  • The Muda Hunting Shows differences in operating mode between identical equipment or teams working on the same equipment.
  • There is a high variability in performance between the teams.
  • There are more and more temporary or new people in the teams.
  • The good results are always obtained by the same people.
  • Small anomalies are frequent and unexplained.

Points of attention

The sustainability of Progress

The PDCA cycle is a concept of continuous improvement integrated into the company’s culture. The most important aspect of the PDCA is the ACT phase, which consists of integrating solutions and sustaining them over time. This phenomenon is represented by the following diagram where a ” wedge ” is put under the wheel to avoid returning to the original situation.

Not putting a “wedge” is tantamount to suffering the punishment of Sisyphus8. Condemned by the gods, he must, considering that there is no more terrible punishment than useless and vain work, spend his life to roll a rock at the top of a hill, a rock that descended every time before reaching the summit.

The Myth of Sisyphus

The harmony of the approach

The Deming wheel represents with harmony and balance the 4 steps. Too often, for fear of being idle, late or even for the sake of going faster than the competition, one is urged to move too quickly to the action while forgetting the steps of preparation or finalization of the actions. This phenomenon is oversimplify as below.

Source: F. Massot (1999) – The dynamic PDCA in a company


1 – D. Sloan (1998) – from the new management equation

2 – W. A. Shewhart (1931)-Economic Control of Quality of manufactured Product

3 – G. Chevalier (2013) – Sustainable public quality: from “doing well” to “Better Living”

4 – J. R. Evans, W. M. Lindsay (2002)-The Management and Control of Quality

5 – M. Röthlin (2010) – Management in enterprise resource planning systems

6 – W. E. Deming (2000) – Out of crisis

7 – J.F. Zobrist (2007) – The beautiful story of Favi: The company that believes that man is good

8-A. Camus (1942)-The Myth of Sisyphus

J. G. Abraham, G. Teneau (2009) – Guided Guide to standards and benchmarks

Mr. F. Stankard (2002) – Management system and organizational performance

K. Bose Tapan (2011) – Total Quality Management

A. Chardonnet, D. Underlayment (2003) – The Guide to the PDCA of Deming

M. IMAI (2007)-Gemba Kaizen, the art of manager with common sense

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