Work Standards and Standardized Work.
Both play foundational roles inside Toyota Production System.
My understanding is the following;
Work Standards define the contents of work not impacted by the customer volume. To improve work standards should get the approval of the technical specialists.
Standardized Work defines the contents of work that must change according to the customer volume. This is the part that we should be improving every day.
Work Standards and Standardized Work.
Because of the similarities in the word, it isn't apparent. Both are part of one system. I read in Hirano’s work that one is for a certain kind of process, which is wrong. Both are required in all operations.
Traditional thinking has defined a standard and keeps those the same for a long time. I know many resist such a statement. Many will say that the standards should improve, and it is written in textbooks that way. Yet, there is no discussion about the frequencies of improvement. I have met many operators who claim their work has stayed the same for years. “Why are you changing now?” It is time-consuming for a specialist to make good standards. And, if there is one, it is typically left like that for years, if not a decade.
To some degree, the traditional thinkings are right. Many aspects of work should remain the same, or if improved, it should be done cautiously. Many things do not change daily. If those did, those changed elements would cause huge performance variations.
Here are some items;
Safety - safety is paramount, and safety standards should be strictly defined and followed all the time. There are many government regulations to follow. Companies might have additional rules in place. These regulations and rules must be followed at all times. And they don’t change very often. If a change, that should be done with scientific methods. It should not change because we have a new safety manager.
Quality - Quality standards are similar. These standards should be designed to match the customer's requirements. These should be developed with scientific experiments. These should not change based on opinions. Sometimes even a quality specialist tries to change things based on opinions. When that happens, the organization loses credibility on standards.
Tools - “In my previous work, we used a faster tool.” Very often, changing a tool becomes a subject of improvement. Although not bad, the device requires delicate physics according to the materials and product design. It should not change randomly. Also, all tools require some maintenance to function correctly. These pieces of information and rules should be captured. These should not change without the scientific assessment of an engineer. Many operators learn the science based on experience, and they can suggest. But operators or anyone should not change without engineering inputs.
Intuitions and tips - some works have intuitions and tips. Instead of waiting for the operators to figure out those techniques, having a guide will help them learn. The documentation process helps the coaching side organize the technics exactly instead of keeping them as a mystery. Of course, just having a document doesn’t mean anything. We do need someone who can show how things are done. But documentation helps to organize. Having both documents and coaches can transfer the skills organizationally.
These are some of the content which work standards should capture. Work standards are open for improvements. But those require specialists’ input.
Kaizen’s main target is Standardized work. Kaizen is a daily continuous improvement. Some things should improve on daily bases.
What standardized work described are;
The quantity of work should adjust according to the customer demand volume.
We waste many motions and waiting between work elements (described in work standards).
Ohno describes Standardized work in the following way.
“What is critical in Standardized work is considering all requirements required to execute efficient production and effectively combine material, machine, and human work. In Toyota, this combination process is called work combination, and the summarized output is called standardized work.”
Taiichi Ohno “Toyota Production System (1978)” [Translated by Hide Oba]
“All requirements” are described inside work standards. It will be placed as symbols and lines inside standardized work. Those lines that do not have a work standard are the ones that we should investigate as waste.
By separating the two, TPS allows an organization to improve on daily bases while sustaining many critical aspects, such as quality. Without the two, work standards and standardized work, what should improve daily becomes vague and dangerous. Kaizen is not risk taking process.