Muda

Muda means waste, where waste is any activity that does not add value. Reducing or eliminating muda is, of course, one of the fundamental objectives of any quality-oriented person.

Taichi Ohno of Toyota identified what are called the seven wastes or seven mudas, being the most common form of muda found:

Waste from overproduction

Which leads to excess inventory, paperwork, handling, storage, space, interest charges, machinery, defects, people and overhead.
It is often difficult to see this waste as everyone seems busy.

Waste of time in waiting

People may be waiting for parts or instructions.
Mostly they are waiting for one another, which often happens because they have non-aligned objectives.

Transportation waste

Poor layouts lead to things being moved multiple times.
If things are not well place, they can be hard to find.
It can aggravate alignment of processes.

Processing waste

Additional effort may be required in an inefficient process.

Inventory waste

Excess buffer stocks a whole host of sins, which will be uncovered by gradually lowering inventory (doing it all at once will cause total breakdown!).

Waste of motion

This includes movement of people, from simple actions when in one place to geographic movement. Having everything to hand as it is needed reduces motion muda.

Waste from product defects

Defects cause rework, confusion and upset a synchronized set of processes.

A simplified view of muda is:

Wasting time.
Wasting a consumable resource, such as materials.
Causing dissatisfaction (including incomplete satisfaction).

Muda is one of the '3Ms': muda, or waste, mura, meaning irregular, uneven or inconsistent, and muri, meaning unreasonable or excessive strain.

The acronym 'DOT WIMP' can be used to remember Muda wastes (Defects, Overproduction, Transportation, Waiting, Inventory, Motion, Processing).

A variant on Mudas is sometimes called the '8 Wastes of Lean', changing 'processing' to 'over-processing', and adding under-use of skills. This has the acronym 'TIM WOODS' (Transport, Inventory, Motion, Waiting, Over-production, Over-processing, Defects, Skills).

Muda

See also: