Lean Six Sigma

8 Types of Muda Waste in Lean – TIM WOODS and DOWNTIME

Lean Manufacturing

7… or 8 Types of Muda Waste

Many may have learned that there were 7 types of waste in Lean, I am not sure when a lot of the organizations changed to 8, but most that I am aware of added one to reference underutilized staff or skills as being a waste. So we’ll cover the 8 types of wastes in Lean.

Also, depending on who and where you learn it from, the names of the wastes could be different. I believe most organizations keep to the same general definitions, just variations on some of the names. I will cover the two easiest versions of the 8 types of waste that I know of – The “TIM WOODS” list and the “DOWNTIME” list. The lists are nearly identical, differing only in some of the names used for the type of waste and the order of the types of waste.

Video on the 8 Types of Waste:


The 8 Types of Waste

8 Types of Waste in Lean - TIM WOODS

The TIM WOODS 8 Types of Waste

  1. Transportation
  2. Inventory
  3. Motion
  4. Waiting
  5. Overprocessing / Extra Processing
  6. Overproduction
  7. Defects
  8. Skills Underutilized / Non-Utilized Talent


8 Types of Muda / Lean Waste

The DOWNTIME List of Waste


Transportation or Transport is about the unneeded movement of people or parts along the process flow. This waste is the result of processes not being in a logical order or nearby each other resulting in time spent moving goods or people around unnecessarily.


Storage of excess inventory leads to wasted money and wasted space. Goods/product can also be damaged or have their value expire while being stored. There isn’t much worse for a business than having a warehouse full of parts that the customer no longer needs, or dozens of eggs in a grocery store that go bad before anyone buys them.


Movement waste within a specific process, compared to Transport which is basically movement waste of the product between processes. Motion waste includes extra steps or unnecessary movement to complete the process from within the process.

As an example, you may have a person who has to work on entering data into a database and to get the proper numbers they have to regularly consult a thick book – manually flipping through pages. This creates wasted time that can be improved upon.

Waiting (Wait of Time)

Employees sitting around waiting. What are they waiting for? The part to come out of the machine, Dan in accounting to approve budget reports, Linda the analyst to correct a mistake, QA holding things up for quality checks… the list can be infinite. The result is people waiting to do work because another process is holding them up and that waiting is a waste. To reduce the waiting, reduce the reasons why something may cause someone to wait.

Overprocessing / Extra Processing

This is where you give the customer more than they are paying for. Now, in some situations, giving a customer more than what they pay for can lead to goodwill between the customer and the producer. This goodwill may pay for itself down the road – but this is not the case when it comes to overprocessing.

Overprocessing waste can be about seeking absolute perfection – when allowable tolerances are so far exceeded that the costs increase but the actual difference to the product isn’t very noticeable and as such value gain to the customer is not present. The customer doesn’t notice or care about the extra effort you put in.


This can lead to a rise in another type of waste – Inventory. This is primarily where you produce too much. This is especially wasteful when you have other things you could be doing to add value or it causes you to not be able to produce other types of parts.

You made too much food in the kitchen and no one wants to take home the leftovers. You also used up all of your ingredients and now you can’t even make a decent breakfast in the morning.

Types of Lean Waste Example


You produce junk – scrap parts, errors in reports, messed up food orders. If you are lucky you can rework it for minimal costs, but it is still a waste. You have wasted your time and resources building it, wasted your time reworking it, and possibly wasted money filling up garbage dumpsters full of the junk you created.

Skills Underutilized / Non-Utilized Talent

This one seems so obvious, only falling behind defects as to the obviousness of it, that I am surprised that it was the new addition and wasn’t considered a waste before. To be fair, I learned this list as originally 7 wastes and I never caught it either. It seems so obvious now.

This is where the organization fails to use the skills and knowledge of its employees. You have a world-class master programmer and you have them debugging HTML code. Maybe it’s what your business needs right then, but find a better way to utilize those skills.


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