PDCA cycle

"It [The PDCA cycle] is a flow diagram for learning and for improvement of a product or of a process." W. Edwards Deming

The PDCA (Plan-Do-Check-Act) cycle, also known as the Deming cycle or the Shewhart cycle, is a project management method used to improve continuously the quality of a process or a product. This cycle is based on the four following phases: Plan, Do, Check, and Act.

• In the Plan phase, the problem to tackle is identified and an action plan is set up.
• In the Do phase, the plan is put into action by the project team.
• In the Check phase, the differences between the results and the expectations are evaluated.
• In the Act phase, corrective actions are taken in order to improve the evaluated situation.

By breaking down a complex problem into these four stages, the organization obtains a clear overview of the situation and is forced to systematically identify areas of improvement, take actions to improve them, compare the results and the expectations, and make the necessary adjustments.

The PDCA cycle is an iterative method, which means that at the end of the fourth phase, it is recommended to implement again the method on the new situation to continue the improvement of the product or the process. This iterative approach results in an increase of efficiency and effectiveness inside the organization.

Developed by Eric Vincent Vong

Presentation of the method

The PDCA method has four phases, each leading to the other, and aims to establish a virtuous circle to improve the quality of a product or a process.

Plan

It is the most important phase in project management because it is mandatory to think about the objectives and define them before acting. Usually, this phase is carried out in three stages.

1. Identify the problem to solve, using for example the method of the five Ws or the brainstorming.
2. Understand the causes, using for instance the Ishikawa diagram.
3. Find the solutions by defining an action plan.

Do

It is the moment to implement the action plan. It can be done, for example, by creating the prototype, carrying out tests, writing the software code, … In this phase, each team inside the project team works on its side, according to the action plan. Be careful, even if each team works on its side, it is essential to have regular meetings with the whole project team to avoid the tunnel effect and to keep a global overview of the progress of the tasks, because some tasks can impact another one.

Check

The project team makes sure that the solution that has been developed (in the Do phase) to tackle the problem (identified in the Plan phase) works well. The easiest way to do that is to compare the results with the expectations in terms of key performance indicators. Of course, this analysis will emphasize differences. But it is normal, and it is essential to keep these differences in mind for the next phase.

Act

This phase is usually carried out in two stages:

1. Corrective actions are taken in order to reduce the differences between results and expectations identified in the Check phase.
2. The project team draws conclusions of the whole four phases and uses it to begin again the PDCA cycle, by capitalizing on the knowledge acquired.

Visual representation

The most important idea to remember about the PDCA cycle is that each iteration must lead towards a better situation, a better quality of a product or a process. To remember this idea, the PDCA method can be represented with a block behind the wheel, which prevents it from going back and which symbolizes the capitalization of the knowledge.