KaizenLean Manufacturing

Prioritizing the Elimination of the 7 Types of Waste

By Jon Miller Published on October 3rd, 2007

Tim Wood helps us remember the 7 types of waste, but he does not teach us about prioritizing the elimination of the 7 types of waste. “TIM WOOD” stands for Transportation, Inventory, Motion, Waiting, Overproduction, Over-processing, Defects but this is by no means the priority in which to attack the wastes. The following is a more common sense approach.
Priority #1. Overproduction is the worst of the wastes because a) it multiplies the other 6 wastes, and b) it hides your true capacity, thereby causing you to make bad decisions such as turn work away or invest in unnecessary additional capacity.
Priority #2. Defects come next because it is as close to pure waste as you can get when you produceunacceptably poor quality. Time, energy and materials are consumed needlessly, and if the customer is not lost, you still need to do the work again.
Priority #3. Inventory is a good candidate for the next worst of the 7 wastes. It ties up cash, requires labor, energy and fixed assets (warehouse) to manage it, and perhaps worst of all provides a false sense of comfort by hiding problems (buffering).
Priority #4. Motion waste is a close candidate for inclusion in the top 3, and may even be number one if the human movements are injurious or unsafe. In terms of ease of elimination and size of improvement impact, the waste of motion ranks very high and is often the target of kaizen.
Priority #5. Processing waste simply means that a process is not necessary or uses more resources (energy, steps, time or materials) then the customers’ needs require. These are quick wins once identified, and can be high impact but are not as common as the other 6 types of waste.
Priority #6. Transportation is quite visible and clearly adds no value, yet by itself not such a huge waste. This waste can shoot up the priority list whenever it increases the chance of defects (damage), processing (tagging, logging items in and out, counting) and creating inventory (moving in batches to save travel).
Priority #7. Waiting is the least harmful because at least you are not consuming resources other than labor, and by not overproducing, transporting, or wasting motion the chance of accidents, defects and creating additional inventory is minimized. As hard as it may be, it is best to tell people “Wait, don’t overproduce” so that they can pull the andon cord and make the problem visible.
This list is manufacturing-oriented. For healthcare, defects is by far the first highest priority waste for all out elimination. Defective parts you can scrap or correct, but people not so much. For various other types of knowledge work, the relatively high cost of labor and low cost of materials brings waiting and processing to the top of the list and may move inventory down the list. For distribution operations whose main value is storing and moving things, inventory and transportation may need to be understood differently to give meaningful priority to attacking the 7 types of waste.
Getting rid of the 7 types of waste is fundamental to the Toyota Production System and to building a Lean culture in any enterprise. There is no clear prioritizing by badness of the 7 types of waste in the classic TPS literature, and deep debate on this topic is probably time that could be better spent making even one small improvement on the gemba.

  1. Keerthi

    October 4, 2007 - 7:54 am

    In his book Workplace Management Taichi Ohno said to get rid of ‘Screws’ and use ‘rivets’ since labour cost of fixing a screw with a screw driver take long time hence ‘cost of fixing screw’ is much higher than the cost of a screw. Waiting is a bigger waste; certainly not the lowest in priority order I think. Would love to hear from Mr. Bill Waddell.

  2. Alberto

    October 4, 2007 - 8:02 pm

    Hi Keerthi. I’m guessing the ‘Waiting’ waste it’s moved to the last place because when you focus on eliminating the other 6 wastes you’re eliminating this as well.
    If you minimize inventory, overprocessing or transportation your waiting time reduces too.
    and as you said, time has it cost but when you overproduce you not only waste time but also resources.

  3. John O'Donnell

    October 5, 2007 - 5:32 am

    Another way I like to communciate waste is with the acronym, DONWTIME (including an 8th waste).
    Not using people’s minds
    Excessive processing

  4. Alberto

    October 6, 2007 - 4:45 pm

    I’d like to share an acronym that worked really well, based on a popular videogame, i’m not sure you’ll understand it because it’s in spanish:
    Transporte (transportation)
    Ergonomía (Ergonomics/Movement)
    Tiempo de espera (Waiting)
    Retrabajo (Defects)
    Inventario (Inventory)
    Sobreproducción (Overproduction)
    Sobreprocesos (Overprocessing)
    so like in TETRISS every waste represents a ‘block’ that we have to eliminate. hope you liked it

  5. Jon

    October 6, 2007 - 4:49 pm

    That’s great Alberto. Very clever!

  6. Nagesh L Talekar

    December 17, 2008 - 1:59 am

    Some of the literature it is mentioned 9 Types of waste.Apart from above mentioned 7 Types of waste they say (8) Misused Resource (9) Un-tapped resource are also two types of major waste.

  7. Michael Moran

    July 27, 2009 - 8:14 am

    I noticed that you referred to TIMWOODS as a way to remember waste. I created TIMWOODS in January of 2000 and was hoping that you would reference this when using it for educational purposes. I can send you the entire PowerPoint slide show if you would like. It is about 9 pages and includes an illustration of Tim himself. I was known as The Moran3 Company back then and it would be nice to see that legacy of TIMWOODS continue and include his illustration.

  8. Jon Miller

    July 27, 2009 - 10:12 am

    Hi Michael,
    We have used TIM WOOD (without the S) as the result of a challenge to a kaizen team to think of an easy way to remember the 7 wastes. We did this often and have several such as WORMPIT. I don’t remember what year they came up with TIM WOOD.
    If you would like to send your information I would be happy to share your material with the readers of this blog.

  9. Don H

    March 2, 2010 - 11:37 am

    use to work for a company that made aluminium wheels. tworims also works. too bad one of the einsteins that i worked with hoodwinked me cuz he didn’t understand tps.

  10. Gemma

    July 28, 2011 - 6:30 am

    hi Michael,
    i’m just trying to create a poster enabling my teams to meet ‘tim wood’. Do you still have a slide of him/

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