For me, Taiichi Ohno and Shigeo Shingo are a bit like the Lennon and McCartney of waste elimination. Together they frame the technical and social sciences of what we call Lean today.
Taiichi Ohno tells us there are seven wastes that account for 95% of the elapsed time between “paying and getting paid.” Most Lean students utilize an acronym like TIMWOODS as a mnemonic to help them remember each of the seven. Many, however, are seven waste parrots. They can repeat the wastes, but don’t have a deep understanding of their significance.
These wastes, according to Shigeo Shingo are measurable impediments to flow, if we only can see them. Much of Shingo’s writing deals with unmasking waste, hidden from us by our “conceptual blind spots.” Shingo declares, “The most dangerous waste is the waste we do not recognize.” Wastes like MOTION, masquerade as work until we understand that breaking a sweat searching for a missing tool is not really work but something that gets the way of the work and flow of value to the customer. “Elimination of waste,” Shingo declares, “is not the problem. Identification of waste is the problem.”
Students of Lean are advised by Shingo that OVERPRODUCTION, producing more than is needed or producing too soon, is the worst of the seven wastes because it causes more of the other the other six wastes – more inventory, more transport, more waiting, more defects, more waiting and more processing.
Then Shingo adds an 8th waste, unmeasurable in an industrial engineering sense, but nevertheless according to Shingo, worse than all of the first seven wastes: Loss of creativity. Management’s failure to recognize the brilliance and experience of their employees places an insurmountable constraint on the identification and elimination of waste.
Ohno exhorts managers to “go to the Gemba” in order to see the waste and show support for employees. He is not referring to visiting the floor only to review huddle boards: “People who can’t understand numbers are useless. The Gemba where numbers are not visible is also bad. However, people who only look at the numbers are the worst of all.“
Shingo says, “Any reasonable person will try to remove waste if he or she can see it.” On this one point, I must disagree with Dr. Shingo. On a daily basis, in my work, I visit the workplace with operating managers where we observe together waste in its many forms. When we reach out to employees, they share problems and struggles with us, wastes that prevent them from doing their best. But when I return to these sites, even after weeks have elapsed, the waste that employees have shown us often remains. So I’ll add a corollary to the worst and most dangerous wastes: “The most demoralizing waste is the waste that managers DO see in the Gemba and yet do nothing about.”