Tips for Lean Managers

The Seven Steps to Zero Thinking

By Jon Miller Published on February 13th, 2008

There are many misguided ways to explain or to think of lean management. We’ve discussed some of these in the 10 common misconceptions of lean manufacturing previously. It may not be complete but it is correct to think of lean as the Toyota way and summed up as the pillars of kaizen and respect for people. Likewise lean thinking can be summed up as the endless pursuit of the elimination of waste. Zero thinking is a broader yet more sharply focused set of fundamental principles that underly the type of process management we call lean today.
Zero thinking is the refusal to become complacent accept as “normal” things such as accidents, inventory, defects or delays. Although undeniably real, these things must be thought of as abnormal and things to be addressed and eliminated through concerted continuous improvement efforts. We can get to zero thinking step by step, starting with what is most essential and often easiest to address, and then advancing to more complex problems within process management.
These are the seven steps of zero thinking, as we understand them:
1. Zero accidents. Safety first must be a way of life and not just a slogan. Without serious workplace-centered and people-centered daily attention to safety, there is no credibility to other aspects of lean management.
2. Zero defects. This is a much longer road than zero accidents and requires an early start and long-term commitment. Fundamental behavior and attitude changes come first, followed by the more technical aspects of problem solving and prevention. Without safety, you don’t have a workplace and without quality you don’t have a product.
3. Zero delays. Continuous flow of material and information results in finishing the work you started as quickly as possible. This has the benefit of helping you get paid quicker for the work you have put in, avoiding spoilage of your work, as well as getting feedback from your customer sooner. Questioning delays forces us to look at the reasons why we put things down rather than finish them, and then to connect and balance processes so that work moves along smoothly. Much of the time this is due to problems in planning and information flow.
4. Zero inventory. We place inventory in the middle of the list because we shift into looking at material and information flow from a systematic level when we aim for zero inventory. Lowering inventory exposes previously hidden problems throughout the entire process from placing orders through delivery. In simple terms, to compromise on the zero inventory philosophy is to compromise on making problems visible. Zero thinking is a practical philosophy of not compromising the pursuit of these ideals.
5. Zero breakdowns. We might think of breakdowns as accidents that happen to machines and equipment. We need to take care of our valuable physical assets and hardware as well as we take care of our people. People and machines process material and information to make us money. Zero breakdowns comes in at step 5 so that we can prioritize breakdown prevention in ways that support safety, defects, delay and inventory improvement objectives.
6. Zero changeovers. The ideal process is available to produce whatever is needed whenever it is needed. This level flexibility is only possible when there is no artificial economy of scale driven by the desire to avoid time lost to changeovers. Equipment and processes must be designed to make zero changeovers a reality (changeover activity may happen but do not result in lost capacity).
7. Zero waste. Are you surprised to find waste placed last? Since we are addressing some of the 7 types of waste directly in the list above such as inventory, defects and delay, we must think of waste in broader terms here to include wasted space, energy, polluting the environment and even the waste of existing talent or the potential for people to learn and achieve excellence.
None of these are discrete steps that start and end prior to the next step beginning. Think of them as a series of parallel activities that have staggered starting points but go on forever. The purpose of placing the starting point for each of the zero thinking steps in sequence is twofold: you can’t focus effectively on seven areas at once, and you need to know where to start and what to do next. The timing at which you start the next step (while continuing efforts with the previous step) will be different with each organization. You will know if you started the next step too early, take a half a step back and firm up the foundation before moving forward.
One can always argue that inventory is a must-have for warehousing and distribution businesses, or that zero breakdowns does not apply to a pure service organization that has no physical assets to speak of, such as a psychiatrist. The seven steps to zero thinking were organized in that way based on our experiences in manufacturing-type processes so it is very possible that other arrangements are possible. They seem to work fairly well as they are in the various environments we have encountered. However they are organized, we need zero thinking because there are a lot of other areas to work on such as zero emissions, zero landfill, zero carbon…

  1. Mike Gardner

    February 14, 2008 - 8:28 am

    Jon, once again you have eloquently phrased sophisticated and complicated ideas into a clear, thoughtful, and concise summary. The depth of your understanding of lean continues to amaze me.
    Zero carbon, though, is not an appropriate zero toward which we should strive. The data has not shown this is a real problem, the cause and effect are incomplete, and we should not use vital resources trying to fix problems that may not even exist.

  2. Jon Miller

    February 14, 2008 - 9:21 am

    That’s high praise, especially coming from you. I’m honored.
    I take your point on zero carbon. A better phrase may be “zero non-renewable energy” as an ideal. If carbon does turn out to be a root cause of global warming then zero pollution would cover that issue in any case.

  3. Erik Stordahl

    February 14, 2008 - 11:18 am

    When talking to management or out on the gemba, do you ever find any confusion over the “zero inventory” question?
    As I understand it Mr. Ohno originally said that inventory “above & beyond” what you need is a waste and should be eliminated.
    Years later when the rest of the world started to try and get lean, this was interpreted as “all inventory is waste and should be eliminated”. This resulted in the knee-jerk reaction of eliminating more inventory waste than the system was ready for and problems invariably resulted.
    Some took this as an opportunity to say “See? That lean stuff doesn’t work here!” when of course that wasn’t really the case.
    That being said, am I right to understand “zero thinking” as “the ideal”? In other words, in the long term we should shoot for zero inventory, all the while realizing that inventory (Raw, WIP or FGI) may be necessary and can be a powerful tool when used correctly in the short run?
    It seems to me that TPS is rarely a world of absolutes, but rather a world where through thinking and thoughtful application of tools is rudimentary. And yet outside of Toyota everyone seems eager to jump to one extreme or the other. I am wondering if you have seen this as well and more importantly, how do you teach people to use inventory properly in the short term but never become complacent and remain focused on the ideal in the long term?
    Thanks as always for your teachings,

  4. Jon Miller

    February 14, 2008 - 11:49 am

    Hi Erik,
    Yes, zero inventory can be a sticking point for many people.
    One can say that if customers are willing to pay you to build and carry inventory, by definition this represents value. However, if you truly probe your customers’ needs it is not inventory but just in time service they want, so doing this without stock is still the ideal in zero thinking.
    Above all kaizen should be practical and useful to you so if reducing inventory hurts your business, you should not reduce inventory but instead work on eliminating the conditions that cause you to have it.
    Limiting the pieces of inventory to one in hand, and one on an auto cycle process (also called standard WIP) would be a good interim goal towards zero inventory. The standard WIP quantity can be reduced through kaizen. True zero inventory would imply that there is not even one piece in hand to work on so it may not be a practical goal.
    In another bit of Japanese language trivia, the word for “inventory” is “zaiko” which written 在庫. This literally means:
    在 = “to have” or “to be located”
    庫 = “warehouse”
    So if we take a strict interpretation of the exact words Ohno used, we could argue that he was talking about stock piles of inventory in the warehouse and not necessarily all materials within a value stream. In Taiichi Ohno’s Workplace Management he actually says it’s OK to have a lot of raw materials, as long as you don’t have a lot of WIP or finished goods.
    In his other writings he emphasizes the need to cut down lot sizes and work in process so that your operations have the flexibility to produce what is needed when it is needed, in the amount needed. Like the pursuit of perfection, zero thinking keeps you moving in the right direction.

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