Muda is a Japanese term that means "futility", "uselessness", or "wastefulness"). It is a key concept in lean process thinking, such as in the Toyota Production System (TPS), denoting one of three types of deviation from optimal allocation of resources). Muda refers to any constraint or impediment that causes waste to occur). There are two types of muda:

• Muda Type I: non-value-adding, but necessary for end-customers. These are usually harder to eliminate because while classified as non-value adding, they may still be necessary).

• Muda Type II: non-value-adding and unnecessary for end-customers. These contribute to waste, incur hidden costs, and should be eliminated).

Muda is one of the three types of wasteful actions that negatively impact workflow, productivity, and ultimately, customer satisfaction. The other two types are mura and muri. Mura means irregularity or a lack of uniformity, which can result in lost product and wasted time. Muri means overworked, which can be caused by mura or by excess removal of muda.

The elimination of waste is the primary goal of any lean system, and waste or muda is anything that does not have value or does not add value. The Toyota Production System originally identified seven forms of muda or waste, which include overproduction, waiting, unnecessary transportation, overprocessing, excess inventory, unnecessary motion, and defects). By identifying and measuring waste, it is possible to see the reasonable steps to take to combat it.

In summary, muda is a Japanese term that refers to any constraint or impediment that causes waste to occur. There are two types of muda, and eliminating waste is the primary goal of any lean system.