Subtle Shifts in the 7 Wastes of Lean

As followers of the Toyota Way we try to stay we try to stay true to the practices, principles, and values that come out of that great company. There is always a lot more to learn about what we call Lean (TPS). Toyota is always taking kaizen to a higher level.
One of the core practices at Toyota (as well as any Lean company) is the relentless reduction of waste and non value added activities.

About 50 years ago, Taiichi Ohno of Toyota formalized this by identifying 7 types of waste in production.
We learned them, and we teach them as Overproduction, Transportation, Motion, Waiting, Processing, Inventory, and Defects. We have found that these categories are appropriate for describing all non-value activities, if you think deeply about them.
Some organizations have added an 8th, 9th, or 10th waste. We’ve never been tempted to tailor the Lean message for ourselves, and preferred to stick to the Toyota Way. I have to admit that we became rigid, and we were in for a shock when we learned that Toyota in North America (and in English language in general) expresses the 7 wastes as:

Overproduction
Conveyance (instead of Transportation)
Motion
Waiting
Processing
Inventory
Correction (instead of Defects)

At first we thought “The meanings are the same, words are a little different, probably just a poor translation.” But would Toyota make such an error? Let’s think more deeply about the differences in the two words.

First, ‘transportation’ conjures up images of forklifts, trucks, carts, and large quantities of materials being moved between production and storage facilities. ‘Conveyance’ is typically used to describe the movement of materials between adjacent machines on conveyors or materials presentation to assembly lines via carts, chutes, etc. When you visit a Toyota factory, you won’t see forklifts in the plant. Bicycles, AGV (automatic guided vehicles), tuggers, definitely doing something that looks a lot like transportation, but in routes according to a set sequence, timing, and specific content and quantity of material. It is a much more refined process that still adds no value, but perhaps deserves to be called “conveyance.”

As far as ‘defects’ vs. ‘correction’ the difference is obvious and huge. The word ‘defects’ conjures up images of bad parts, scrap, poor quality escapes, and rework. ‘Correction’ suggests that an error was caught before being passed on downstream and corrected. At a basic level it’s the difference between end-of-line inspection and in-process inspection, detection vs. prevention.
The Japanese words Toyota uses for the 7 wastes haven’t changed, as far as we know. Perhaps this is thinking too deeply on the meaning of two words. But it would be cool if the word choices in English were intentional, signaling that Toyota had ‘graduated’ from ‘defects’ to ‘correction’ and ‘transportation’ to ‘conveyance’ after 50 years of kaizen.

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