In this series of posts, I briefly described the seven kinds of waste identified by Taiichi Ohno and other creators of the Toyota Production System (TPS). Identifying instances of each kind of waste in a production process and eliminating them is at the very heart of lean production. Again, the “lean” in “lean production” refers to the lack of waste in the process.
To review, the seven wastes (often called the “7 W’s” or “seven muda,” the Japanese word for waste) that are found in a production process are:
Looking at the 7W’s all together, you can see some patterns among them:
- Most of them involve doing or having too much of something, whether it’s keeping too much stuff on hand, moving people or objects around too much, or spending too much time doing things that aren’t needed, making things that aren’t needed, or even doing nothing at all.
- Each kind of waste is intertwined with every other kind, to the point that any increase in one kind of waste often leads to an increase in other kinds of waste, and decreases in one kind of waste can lead to a decrease other kinds of waste.
- Each kind of waste is both a practical problem and a camouflage for unresolved conceptual problems. Inventory buffers hide poor supply mechanisms; overprocessing hides defective work techniques; waiting hides faulty transportation patterns, and so on. Getting rid of each type of waste doesn’t just solve the immediate problem, it uncovers the design issues that are being obscured by it.
- Each kind of waste is an obstacle to flow. The highest goal of any lean process is for it to flow smoothly like a river from beginning to end. Friction wastes energy and resources, and leads to defective and unsatisfying results.
In these commonalities, a vision of lean production can start to take shape. A lean process is one which flows smoothly from start to finish with no obstacles or barriers. Anything that might block or slow the flow is eliminated, an effort that rapidly accelerates as reducing one form of waste in turn reduces other forms of related waste and a feedback loop develops. Fundamental conceptual problems that were obscured by waste are resolved and replaced by new, better visions. All of this keeps on happening, day in and day out, as the continuous process of improvement endlessly refines the process to achieve cheaper, easier, higher-quality results.
There’s nothing magical about the number seven. The TPS could easily have defined five forms of waste, or ten, or dozens. Many wasteful actions in the real world may actually fit into none of the classic categories, or into several. The 7W’s are just rules of thumb to help identify the wasteful parts of a production process and start to correct them.
When thinking about creating a leaner everyday life, it’s worth remembering that finding the seven wastes is the beginning of the process, not the end. It’s not about how many waste categories you can check off, it’s about whether the process is flowing more smoothly, more error-free, more cheaply, and more satisfactorily than it was before. Anything that gets in the way of those goals, whether it’s clearly described by one of the 7W’s or not, is a candidate for reduction or elimination.
Imagination is the only limitation.