Waste Identification and Elimination
This section covers waste identification and elimination. The exam tests whether you can see waste at the gemba, quantify it, and remove it without creating waste elsewhere, including in office and service processes where Gold candidates often work.
The eight wastes (TIMWOODS)
Transportation, Inventory, Motion, Waiting, Overproduction, Overprocessing, Defects, and Skills or underused talent. Overproduction is usually ranked worst because it creates the other wastes and hides defects. Mura (unevenness) and muri (overburden) are causes; muda is often the visible symptom.
Worked example
An operator loads a machine, waits four minutes for the cycle, unloads, and repeats for 60 cycles in a 480-minute shift. Waiting is 240 minutes, half the shift. A supervisor proposes buying a second machine. Reasoning: the machine is not the constraint; the operator's idle time is. Converting internal to external work with a second fixture lets the operator load while the machine runs, removing the wait and raising output at no capital cost. Buying the machine would add capacity, inventory, and muri.
Waste walks should record what is observed, where, and how often; frequency matters as much as the type.
Traps that cost marks
- Listing wastes without evidence or a measured baseline.
- Relocating inventory instead of reducing it.
- Confusing busy work and motion with value-adding work.
- Treating waiting as machine time or system response.
- Ignoring the waste of unused talent in knowledge work, where overprocessing and waiting dominate.