More musings on “Muda” (Waste)

Let us return to the slogan “Muri, Muda, Mura,” and see if there is something new to say about Muda, the one that is discussed to death. Just in this blog, it is already the subject of the following four posts:

  1. “Muda” just means “Unnecessary”
  2. Management Whack-a-Mole and the Value of Lean
  3. A factory can always be improved
  4. Occam’s Razor, Value Added, and Waste

What more is there?

Definitions of waste

In daily life, a “waste of time” is an activity that you can stop doing without any adverse effect. It is no different in manufacturing: an activity is “muda,” (waste) if you can stop doing it without lowering your performance in any way; a device is “muda” if you can dispose of it and nothing gets worse. Stopping overproduction, for example, won’t hurt your quality, productivity, delivery, safety, or morale. It is a simple and actionable idea: if you look closely enough at what you are doing on a manufacturing shop floor, you can tell in those terms what is necessary from what isn’t.

Many authors, however, feel compelled to make it more complex, more abstract, and less actionable. Following are a few examples of attempts to define waste — as a translation of Muda —  that I think are generating more heat than light:

  • Anything that does not physically change the product. Shipping does not physically change the product. Yet, unless we can manufacture at each customer site from materials extracted from the ground right there, delivery is impossible without shipping. Packaging prevents the physical form of the product from being changed during shipment, which would make it defective. Calling packaging or shipping “waste” when both are obviously necessary to order fulfillment is. at best, confusing.
  • Anything that the customer is not willing to pay for. Manufacturing involves many tasks that customers need not be aware of, let alone express a willingness to pay for. You don’t ask customers whether they are willing to pay for revision control on engineering changes. If, however, you stopped doing revision controls, the consequences on quality would be dire. Therefore it is not waste.
  • Not doing things right at the first time. This brands as waste any activity that requires experimentation or iteration.

Ohno’s list

Ohno’s list of seven types of waste is the subject of countless PowerPoint presentations,  most of which I find not only tedious, but actually misleading. The most common misconception is that the seven list entries are mutually exclusive categories. The point of Ohno’s list is not to categorize the waste but to help you recognize it when you see it. It guides your observations when you walk the shop floor. The items in Ohno’s lists are symptoms rather than categories. You can observe both overproduction and excess inventory, but they are obviously not independent phenomena.

Ohno’s list has seven elements because it is Japanese, and seven is a lucky number in that culture.  Other Japanese lists of seven elements include the old 7 tools of QC and the new 7 tools of QC. Akira Kurozawa’s movie is the Seven Samurai, and the samurais’ way of the warrior specifies seven virtues… It may be related to Buddhism having seven factors of enlightenment. Although it also has lists of seven, like the deadly sins or T. E. Lawrence‘s biblical Pillars of Wisdom, the Judeo-Christian world prefers lists of 10, like the 10 commandments or the US bill of rights.

I think this is one cultural reason so many want to expand Ohno’s list. All sorts of additional entries have been proposed, including skills, unused competence, unused space, government, meetings, unemployment, complexity, poor communication,… It is not clear to me that such additional entries belong in parallel with Ohno’s seven or help you identify waste on a manufacturing shop floor. As  Rogério Bañolas pointed out, however, Ohno’s list is not necessarily on-target in activities other than manufacturing.

There are also practical considerations about the length of lists. Seven entries is about as many as people can remember. Lists of ten are too long: few Americans can tell you what the 8th amendment to the US constitution says, and only the most devout Jews and Christians can recite all the ten commandments. Lists of 14 even worse, like Woodrow Wilson’s or Deming’s 14 points, to which I would add Jeffrey Liker’s 14 principles of Lean in The Toyota Way.

TIMWOOD and possible misunderstandings

Even a list of seven is a challenge to remember without the help of a mnemonic like TIMWOOD, which stands for “Transportation, Inventory, Motion, Waiting, Overproduction, Overprocessing, and Defects.” It is undeniably useful, but we have to be careful in not being misled by it in at least the following two ways:

  1. The sequence of items is dictated only by the need to fit the acronym, and has no implication of priority. Just because Transportation is listed first does not mean it is more important or common than Overproduction.
  2. The words making up TIMWOOD are memory joggers, not definitions. While all Waiting, Overproduction, Overprocessing and Defects is waste, the same cannot be said of Transportation, Inventory, and Motion. As discussed above, delivering products to customers is transportation but not waste. If you literally have zero inventory, you can produce nothing, and some handling of parts is necessary. For these types, as Ohno actually phrased it, the waste is the following:
    • Unnecessary transportation. This includes, for example, moving the same bin multiple times between the warehouse and a production line.
    • Excess inventory. Common telltale signs that inventory is excessive are that no one knows its purpose or that is has not moved in three years.
    • Unnecessary motion. This includes long carries from a shelf to an assembly station, and multiple handling, such as picking a part from a bin, setting it down on the work station and then picking it up again to mount it on the product.

The qualifiers make the explanations a bit more complicated. Without them, however, the list may look more elegant but it does not make sense.

“Just get rid of it!” won’t

Once you have identified waste, all you have to do is get rid of it, right? If only it were that simple! Sometimes it is, but rarely. Most of the time, getting rid of waste involves both technical and managerial changes, and going after each observed item of waste one by one would be ineffective. The list can be very long, and its entries interrelated. That is why you organize Lean implementation in projects to redesign production lines, increase equipment flexibility, or change policies in production control, maintenance, quality, human resources, etc. The waste that is observed is the gold in the mine; the projects, the means of extracting it.

Technically, getting rid of the waste is always feasible, because, by definition, waste is unnecessary. There is, however, a difference between knowing that something is feasible and having done it. That is where Lean implementation skills come into play. Learning of the existence of opportunities is an important first step, but only the first step.

19 comments on “More musings on “Muda” (Waste)

  1. Comment in the PEX Network & IQPC – Lean Six Sigma & Process Excellence for Continuous Improvement on LinkedIn:

    Hi Michel,
    Good Article. In too many instances discussions on wastes preclude that they occur in a vacuum or stand alone incidents. The point we must make is that the vacuum or solo activity is just not the way it happens. If each step of the production process (workstation) is build on the prior step then so are the production wastes. This is one of the major distinctions companies do not ‘see’. Once, the production area layout is changed, once there is an increase in equipment reliability, a change in policy or procedures and human interaction one will see a sharp reduction if not an elimination of the seven wastes. But again this will and does not happen in a vacuum.

  2. Hi Michel

    It is not so much that it is a lucky number in Japan. There is a Japanese expression “nakute nana kuse” which means “Even a person with no bad habits has at least seven”. Ohno loved wordplay and when he visited a floor where the managers said they had no waste, he replied “nakute nanatu no muda” meaning “you’ve got at least seven”.

    In both expressions, the number seven is intended to mean “a lot” and not exactly seven.

    Some of Ohno’s students recall him saying after leaving Toyota that “I never said there were 7 types of waste” so it is possible that the 7 came from a combination of Ohno’s twist on the “7 bad habits” expression with efforts at Toyota to codify the TPS in 1973. Ohno’s name is on that document, but he only wrote the introduction.

    More on that here if interested

    • He may never have said it, but either he wrote about it or signed his name to ghost-written text. The list of seven types of waste is in Chapter 2 of his other book, The Toyota Production System.

      After reading your excellent translation of Workplace Management, I suspected that The Toyota Production System had been, if not ghost-written, at least heavily edited by Public Relations and that the real Ohno was the plain spoken and direct man we encounter in Workplace Management.

      Even if seven is used to mean “many,” other numbers could have done that as well, such as 10,000 as in “Banzai.” The fact remains that there are many lists of seven in Japan, and I still don’t think that, in this culture, we would have made the same choice.

  3. Sithembiso Dlamini asked the following:

    Reading about different facets of waste – comes in mind waste as a result of meeting, cutting down meetings can save Industries huge money. especially Middle to Top Mngt. Is there a tool used to calculate the cost of meetings ?

    The only one I have seen used is to add up the labor cost of all the participants for the duration of the meeting. This is questionable for several reasons. First, not everybody knows, or should know, how much money everybody else is being paid. Second, this is not cash that would be saved if the meeting did not take place.

    Rather than thinking in those terms, I think it is better to just apply well-known principles on meetings:
    1. Have a purpose that is communicated ahead of time to all participants, including a statement of the desired outcome.
    2. Invite everybody who can contribute, and nobody who can’t.
    3. Publish an agenda.
    4. Let all participants know what they should prepare.
    5. Run the meeting with discipline: allow no phone calls, no personal work on laptops, no side conversations.
    6. Publish minutes promptly, for example by writing everybody’s commitments on a copy board and printing them at the end of the meeting.

    If you do this sort of things, nobody will complain that your meetings are a waste of time.

      • I do not believe that yoko tenkai means benchmarking but “lateral development,” which means sharing what you are doing with your peers. Benchmarking is evaluating the practices of other organizations in search of ideas you can apply in your own.

  4. excellent thoughts on meetings. I found this to be an excellent read on meetings…

    Read This Before Our Next Meeting by Al Pittampalli

  5. Comment in the Global Lean & Six Sigma Network discussion group on LinkedIn:

    I think the original phrase was “Muda, Mura, Muri”, the thinking being that this was the logical sequence of improvement: remove waste that leads to unevenness inoperations, which leads to overburdening of resources.

    Later, it was suggested that the sequence should be “Mura, Muri, Muda” because of the mura (unevenness) of trying to “make the numbers” at the end of reporting periods. This causes sales to write too many orders toward the end of the period and production mangers to go too fast in trying to fill them, rather than focusing on the routine tasks necessary to sustain long-term performance. This causes equipment and employees to work too hard as the finish line approaches, creating muri (overburden). This in turn leads to downtime and mistakes creating waiting, correction, and conveyance waste (muda).

    So, this thinking is that mura creates muri that undercuts previous efforts to eliminate muda. Or, in other words, mura and muri are now the root causes of muda in many organizations, even putting muda back that have already been removed once.

  6. Hi Michel, very good article. I appreciate your review points and clarification examples. I agree with you to properly ‘see and define waste’ is critical to a Lean transformation, implementing methods of eliminating waste without adding some other waste or degrading productivity, delivery, safety, morale and quality are essential. The problem, I run into most often is managements lack of faith that a learning organization is better equipped to transform the environment, through organization, employee suggest, problem solving and group information exchange and accountability. Most managers I know want to see improvement, but they do not want to be bothered with getting involved or being apart of the solution, until they perceive a concern: workers stopping the process for a few minutes to problem solve, not clocking-out promptly at the end of shift, or the waste identified requires the manager or supervisor to change behavior.

  7. Comment in the Lean CEO discussion group on LinkedIn:

    Great post @Michel. The more I reflect, I think it is time for the Lean practitioners to emphasize muri and mura as much as we do muda. They all need to be considered in concert. Too often I have seen organisations focus on muda to the point of creating muri. Thanks again for the thoughts.

  8. Comment in the Lean CEO discussion group on LinkedIn:

    Typically when I work with people on the floor it is very easy for them to see MUDA. When I ask them what problems they see, they list many issues all of them related to MUDA (too much walking, inventory, rework etc…) Then I asked them to do job, all of a sudden a new list comes out but more focused on Muri and Mura. Things they experienced/felt, what the team members feel. For me this is what we start focusing on. For me this creates “respect for people”. It will be amazing what an impact it will have on the members.

  9. Comment in the Lean CEO discussion group on LinkedIn:

    Good approach Bryan,
    I have also seen that Muri procudes Mura and as a result Muda. We have power electronics furnaces that were working to the top limit (Muri) at the end a breakdown acurrs. Sincronization in our operations are affected breaking the one piece flows between operations (Mura). After analysis we encounter muda of motion, transportation an waiting in all our processes.

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