Which term represents variability or fluctuation in a process?

• A. Muri
• B. Nesting
• C. Pacemaker
• D. Mura

Answer: (D)

In Lean thinking, variability or fluctuation in a process is described as Mura. It refers to the unevenness in flow, output, or workload that occurs from period to period. This unevenness makes it hard to balance work, leads to bottlenecks and uneven staffing, and often increases work-in-process and delays. The goal is to reduce Mura by leveling production (heijunka), standardizing processes, and stabilizing inputs so the process runs more predictably.

Overburden or strain on people and equipment is called Muri, which is a different issue focusing on pushing resources too hard. The pace of the production line is often set by a pacemaker or bottleneck, which controls the overall tempo rather than describing variability itself. Nesting is related to optimizing layout or how parts are arranged to minimize waste, not the variability in a process.