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Quality check on Standardized Work [Diamond mark]


Do you pay attention to the diamond mark inside a standardized work?

This mark represents “Quality check.” It is essential to build quality into a process.


As a reference, Kaoru Ishikawa, the pioneer of “Total Quality Control,” has left an interesting guideline.

Have you seen it? Do you agree?


And are we paying the attention that we should be paying to this mark?



Inside the Standardized Work Chart, there is a diamond mark [♢]. The pattern represents a quality check. But we don’t talk about it very often.


Kaoru Ishikawa, a “Total Quality Control pioneer,” has left an interesting guideline for “Quality Control Points.” Here is his approach;




First, the “Quality Check” inside a standardized work and the “Quality Control Point” mentioned by Ishikawa are slightly different. Yet, I have learned that expecting something not included in an operator's standardized work is unfair to the operator. Some people keep adding things without clear definitions inside standardized work. The contents, timing, and durations must be included in standardized work. Just simply providing a list of quality checks is not sufficient. If Ishikawa or any quality personnel wants an operator to perform quality control, it must be included in standardized work. The detail of how will be mentioned inside work standards, while the timing and location will be specified in standardized work.


Once the above link of quality control point and quality checkpoint is made, Ishikawa’s guideline on one to three quality checkpoints per standardized work makes sense. First, every standardized work should have at least one quality check. Even the simplest work should have some quality responsibility. Having zero quality checks almost means giving no responsibility. On the other hand, too many quality checks will lead to problems. Are all quality checkpoints checked every cycle? Very often, some are skipped. This is the primary reason why different inspectors result differently. They have a long list of things to check, yet other people conduct part of the checks.


The 1 to 3 checkpoints per standardized work is a guideline, not a strict rule. For example, it is not clear from Ishikawa what is the takt time of work. If takt time is longer, there are likely to be more quality checkpoints. Should that number increase multiple of Ishikawa’s guidelines? I don’t think so. The risk of not checking will become more significant as the quantity of checks increases. The increased takt time means the operator will require more skills and quality responsibilities. Management should see it as high risk. Any standardized work that contains more quality checks than the approach should gain attention from the management.


This creates the need to reduce the number of quality checks. And this reduction should be made in logical or scientific methods. A typical approach I observe after such discussion is that they don’t write the mark on the standardized work while the responsibility still exists. This is unfair and destroys the whole purpose of standardized work. Another approach is they stop checking and take a considerable risk. And blame TPS when a problem happens. Nobody is suggesting taking such a suicidal approach. Reducing quality checkpoints means understanding the checkpoints and the impacting factors and placing controls and poke-yokes toward the factors. A typical problem I look for is duplicate checks. Some believe it will improve when more people check the same checkpoint, adding more duplicate checks. Yet, those duplicate checks lead to this sense that others will check; therefore, I don’t have to be responsible. Everybody’s responsible means nobody is responsible. The quality does not improve in an irresponsible work environment.



Another point.

In Japan, several manufacturing companies are implementing “Pointing and calling,” “Fingernail,” or “Standard call out” at every checkpoint. The idea behind this is that this approach raises the awareness level of humans. The process includes checking by eyes, pointing with a finger, and verbally saying “◎◎◎, good!” And listen to your voice. According to Japan Railway, which started pointing and calling, the method reduces incidents significantly. This approach probably takes more time than just looking at or using a pen. But this stimulates the brain using the eye, finger, mouth, and ear. If we are going to ask to check, why not go it all the way? A mediocre check is the same as waste. Humans are capable of checking perfectly if we use all our senses.

I read that some railways outside Japan have implemented similar activities. Yet, there’s still shyness.



The diamond mark. It’s not a decoration inside a standardized work. It is really important to build-in quality and everything. Are we respecting this mark with that importance in mind?

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