Reference opinion #3. The PDSA fits better with the Theory of Knowledge facet Deming’s later work. Checking is not enough, it presumes you know what is true. Deming asks us to question what is true, to consider the system, the stake holders, with an appreciation for variation as a guide. We are not merely checking.

Deming’s system is the planning and study of actions taken related to manufacturing processes. The study portion is there to increase knowledge about the actions taken. Deming understood that people were not perfect and neither were processes. He understood that all processes contained variation who’s cause was both Common (inherent to the process exa machine setup, employee competence) and Special (effects the process but not inherent to its daily operation exa external power outage). Ignoring this Study step of the functioning process, could result the company not observing variation which is effecting the process which was not thought out or considered during initial planning. Deming knew that every change to a process was not and could not be perfectly thought out, therefore the step of study was added to observe via measurements the end result (whether it be desirable or undesirable or a mix). The Act is in place to start the process over considering what has been learned as a result of the Study.

The PDCA cycle uses check and is all too often; simply verification that predetermined conditions have been achieved (limited focus). It does not indicate that the process needs be studied and determination made as to the results of the study. Check is verification that predetermined conditions have been met while study indicates gaining knowledge of what actually occurred as a result of planned process change. This is why Deming used the word hold back when he saw the word Check substituted for the word Study.

Marriam-Webster defines the words:
Study: Application of mental faculties to the acquisition of knowledge Careful examination or analysis of a phenomenon development or question

Check: A sudden stoppage of a foreword course of progress One that arrests, limits, Restrains – A standard for testing and evaluation – The act of testing or verifying.

Therefore study would indicate determining from analysis what conditions (efficiency, variation etc) are occurring related to a process or its relative changes. Check would indicate a verification that a process change provided some predetermined end result, regardless of the conditions.

Process changes have the ability to provide an end result while mucking up all sorts of conditions. For instance, if a process change placed an operator’s extension and flexion at their greatest lengths but achieved a conforming product, was the change effective? Or, if a process change provides conforming product but a necessity to continually adjust machines, is this desirable? The study of PDSA, would have discovered these things where the check PDCA might allow them to be ignored.

The other failure is to combine PDCA and its siblings 7D and 8D as a companies process for addressing ALL Non-Conformance. These tools are very useful when applied to their intended purpose, which was supplier processes under PPAP control. However I still see many people applying these techniques to ALL their problem solving related to discovered or observed non-conformance. I would caution that processes not under PPAP control should under go good problem solving techniques and not the Automotive PPAP 7D or 8D. The reasoning lies behind Deming’s PDSA and the knowledge of processes which is acquired from study. Further, is the opportunity presented via non-conformance for businesses to perform a Strategic Assessment to consider current state VS desired state, Risk, and Value then choose to completely replace a current process.

I think as long as the cycle is used continually, (i.e. to iteratively develop a change aimed at improvement over time) and other key principles such as use of data over time, making predictions and starting on a small scale, then the labeling of the stages should not matter.

Our systematic review demonstrates a tendency for those using PDCA cycles to only report a single cycle, however I would caution against concluding that this is always the case. Applying the principles of the method can be improved for both uses of terminology. These principles should be the focus to drive learning and improvement, not just capture the narrative of improvement work.

Thanks
Chris

‘stops or slow down the progress of (something undesirable).”efforts were made to check the disease” ‘

Actually strengthens its relevance to process improvement, it doesn’t hinder it. (think countermeasures)

I appreciate the effort to emphasize thoroughness in that step, but arguing over the finer points of word meanings is something people mostly do to try and establish dominance in expertise of a field by making someone else look wrong.

Arguments over minutiae make for great wastes of time when people could be working on applying the concepts to reality.

Opinion #1:
However in the above explanation, why 5 steps are needed to explain a 4-step CI cycle.
IMO, the step# “3.Launch the product” is redundant, hence waste (NVA), and can be removed or can be merged with step #4.

Opinion #2:
It looks like, from the above points, that the real owners of the “PDCA cycle” is the set of unknown Japanese engineers, not Deming. Is it correct.?

Opinion #3:
Deming should have explained how the word “Study” is superior to the word “Check” in this context and In 1986, the did “study” not mean “examine” also. BTW, the word “Check” also means ” examine (something) in order to determine its accuracy, quality, or condition, or to detect the presence of something”.

I am comfortable with PDCA and Deming was known for his clarity of thought and, I am afraid, not for such confusing remarks on trivial matters.

Ari