A Continuous Improvement Tool

A key part of six sigma and lean transformations is empowering people to identify problems and make continuous improvement to processes and procedures.

One common problem solving tool leveraged by many organizations is called Plan, Do, Check, and Act or PDCA.

But tread with caution! PDCA has evolved through the years and some confusion has crept into the DNA.

Warning! Danger lies ahead for six sigma and lean experts who have crafted some alternative version of PDCA. You may become uncomfortable with the balance of this article.

PDCA is said to have originated as the Shewart Cycle, named after the concept originator Walter Shewart. The Shewart Cycle contained Plan, Do, and See.

Edward W. Deming modified the cycle to be Plan, Do, Study, and Act.

Refinements in Japan and the return of these ideas to the United States produced an evolution into what we now call Plan, Do, Check, and Act.

The spirit of the tool is to leverage the scientific method concept of hypothesis, experiment, and evaluation. Hypothesis = Plan, Experiment = Do, and Evaluation = Check. Then, if all is well, you can Act.

Let’s take a closer look at each of the four steps



Identify the problem and develop a plan for improvement:

  • Identify the problem
  • Agree on the desired situation
  • Determine the root cause(s)
  • Select a potential solution
  • Create implementation plan

There is a lot of work in the above activities. The Plan step can be 75% of the entire effort.

Some of the tools that can help during this step include:

  • Brainstorming
  • Cause and Effect Diagram
  • 5 Why Questioning
  • Run Chart


Test your solution:

  • Implement on a trial basis
  • Take measurements

At this point, keep in mind that you are not “doing” a full implementation. You are only testing a possible solution.

This step can be confusing:

  • One website claims that Do is “about the implementation and realization of the planned improvements of the entire process.” This implies that Do covers everything.
  • Going in the opposite direction, one over-priced workshop claims to teach you that Do is “analyze the causes” and ignores any mention of running a trial to obtain measurements.

Both of the above are classic examples where so-called experts are confusing the rest of us.

If you stick with the evolution from the scientific method, then it’s clear that Do is about Experiment. It’s not doing everything in the scope of your Plan, nor is it analyzing the causes.


Evaluate the results:

  • Compare your measurements to expectations
  • If problem persists, then return to the Plan step
  • If success achieved, then proceed to the Act step

As we saw with Do, some charlatans sow confusion with everything they say. In one example, the know-it-all claims that Check is about “improving the process” rather than analyzing the measurements from the Do step.

Staying with the scientific method, then it’s clear that Check is about the evaluation of experiments regarding your hypothesis.



Fully implement the solution:

  • Update documentation on new standard work
  • Train everyone in the new procedures
  • Apply improvement to all areas
  • Monitor performance

This step can also be confusing. Some call this Adjust. Others say this is React instead of Act. Someone even proclaimed that the fourth step is Proact – whatever that means.

Hats off to those that overcome the confusion and actually accomplish something!

One additional note is how many self-proclaimed gurus suggest you are never finished. They claim that after you complete the Act step, you then return to the Plan step and begin again. At first glance, that sounds nice. But, that implies every PDCA you ever did is still active.

Pros and Cons

PDCA is a problem solving tool that many organizations use all the time. Others have struggled and not found value in the tool.

When and where to use PDCA is part of the issue. Some claim “PDCA is usually associated with sizable projects … seeking breakthrough improvements.” Others apply during “kaizen blitz events seeking frequent small improvements.” And, of course, some claim you should use PDCA everyday for every problem – a violation of the common sense notion that “if all you have is a hammer, then every problem looks like a nail.”

Let’s look at the Pros and Cons:


  • Tool is very easy
  • Lots of people use it
  • Only tool you need
  • It works


  • Steps are confusing
  • Lacks sustainability
  • Other tools are better
  • It doesn’t work

One big challenge is how the fine print for Plan suggests this first step is 75% of the total effort and is really multiple steps.

Another challenge is the assumption that the Act step is not the end and the team is really in an endless loop of repeating PDCA forever. Does this mean that you could end up with 100s or 1,000s of active PDCA teams working infinite loops?

And historians warn us that, founded in 1884, the Painting and Decorating Contractors of America (PDCA) is a national trade association dedicated to the success of painting and decorating contractors through ethics, education, and excellence.

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