Three Forms of Waste

In lean you have three types of waste.  Mura is unevenness in work demand or work flow. Muri is having a greater demand than capacity in any given time or overburdening the process, series of processes or system. We can all relate to making mistakes when we are rushed or stressed this is caused by Muri. We establish the capacity for work then ensure we do not try and force more into the system than it can handle.

Muda waste has two types:

Type 1 is the necessary but non value adding waste. This is where from a business perspective we do it to meet regulations, cannot afford to duplicate, such as pharmacies on every floor of a hospital, photocopiers, faxes and printers on every desk etc.

Type 2 is unnecessary, non value adding waste.

Muda, Mura, Muri

This is not some magic spell, but 3 Japanese words that are often used to describe the Lean process in action.  Actually, they would be better used to describe what is being changed or improved.

  • Muda is the word for waste, and as we’ve already said on the previous page, Lean is all about removing waste.
  • Mura describes unevenness in a process; a stopping and starting process or variable volume process rather than a smooth and constant process.
  • Muri refers to overburdening or placing too much upon one thing.


Where you push a production machine to perform above its capability – the end result is likely a broken machine and potentially poor quality products.  So, this is about not just reducing waste, but optimizing how you remove that waste by maximizing efficiency and logistics. Consider this simple example:

You are given the job of moving 6 tons of earth and you have four 3-ton trucks available.  You can choose to put all 6 tons in one truck, but this would likely break and fail – MURI.  You can fill the first truck with 3 tons and then put a ton in each of the other 3 trucks, but this is uneven – MURA and wasteful of available space – MUDA.  You could send the same truck twice, but this would be time wasting – MUDA.  You could put the same amount in each of the four trucks but then everyone would be wasting capacity – MUDA

The most efficient and effective way is to send 2 trucks at the same time with 3 tons in each – maximizing capacity and minimizing waste.  In fact, you probably knew the answer to that problem without thinking too hard, which shows that your natural inclination is to be lean and effective.

The Seven Elements of Waste

  • Muda
    • Transport
    • Inventory
    • Motion
    • Waiting
    • Over Producing or
    • Over Processing
    • Defects
      • Skills


The 7 classic wastes include overproduction, inventory, defects, over-processing, waiting, motion and transportation. An eighth element of waste is emerging called “knowledge and latent skill”. This is where organizations fail to take advantage of skills or talent or not effectively transferring learning between employees. These wastes can be found by determining the rolled throughput yield.  A further explanation of each individual term follows.

TIM WOODS may also be referred to as the 8 wastes as there are 8 letters in TIM WOODS.  The ‘S’ represents Skills