The Necessity of Redundancy

After every major natural disaster that disrupts global supply chains there are voices that cry out “A-ha! I told you just in time doesn’t work!” So with the Icelandic volcano turning European skies airoplane-free for a few days. News programs report shortages of critical raw materials, such as bananas in Germany. Although the skies seem to be clearing, extended across weeks such a situation could threaten to shake the foundations of the industrialized West. If I had power to influence the future of aviation, blimps would play a major role, their bulbous forms filling our skies, uninhibited by jet-engines which clog with volcanic debris.

Lean systems promote problem solving to drive out waste, which is exposed by just in time flow, work that is triggered by pull from the downstream (customer) process and that is paced by customer demand. Inventory is reduced not only because of the costs associated with owning and managing it but because inventory acts to cover up weak spots in the supply chain. But once exposed, these weaknesses need to be either shored up or covered by redundant stock, systems or resources. Since not all problems can be immediately solved, unless we accept that we allow supply chains to run dry from time to time, redundancy is a necessary part of lean systems, though never value-added or an end in itself.

This may be a counter intuitive thought, but in fact lean systems demonstrate many examples of the necessity of redundancy. Lean requires buffer stock inventory required to account for delivery lead time. It requires safety stock inventory required to account for delivery failures and losses. Within standardized work, recovery time built into a worker’s cycle for repetitive operations to avoid fatigue. We could call this necessary redundancy. Using a skill matrix and cross training program to develop multiple people to perform the same task even when most days these skills may be “idle” is yet another example of built-in redundancy which adds no value but avoids the waste of system breakdown should there be an absence of a skilled person to perform the work. And the designer who convinced me that the time he spent walking around the office thinking and being inspired was not motion waste but necessary secondary energy expenditure while his brain worked on the chief process of design, he taught me about the necessity of redundancy.

Duplication of suppliers to insure competition, part availability or even multiple designs. The lack of this last type of redundancy in part design may have been a factor in Toyota’s recent and expensive quality problems. According to an International Business Times article titled Toyota stumbles but its “kaizen” cult endures suggests that these problems “…highlight an often overlooked problem with its obsessive focus on hyper-efficient supply chains.” Namely,

Sure, fewer parts and fewer suppliers can drive down material costs and radically simplify operations. But when a strategic supplier of a critical part encounters a hiccup, it can have crippling and costly implications for the enterprise.

The article goes on to make a “Darwin versus kaizen” analogy:

Alex Blanton, an analyst at Ingalls and Snyder who has covered the U.S. industrial space for four decades, says that in this respect, companies that adopt Toyota’s lean principles are ignoring the lessons of evolution.
“One of the ways Toyota has reduced costs in their lean program was commonality of parts,” he said. “Well, if that part has a problem, then it effects many more models. If they’d been using a lot of different gas pedals for these models, and they had problems with one, they wouldn’t have to shut down the company.

“That’s why humans aren’t lean.” Blanton said. “It’s a Darwinian thing. The purpose of fat is to carry you over periods when you don’t have food.”

Perhaps in designing our supply chains we should learn from self-sustaining, low waste, renewable, solar-powered, green systems that have persisted and improved continuously over geologic time. Ecosystems do not sub-optimize around the land, the organisms or the food, they are inherently stable. Ecosystems aren’t global, they are exceedingly local. Ecosystems aren’t lean, they are fit. If we want to imagine the future of industry, instead of lean manufacturing, which may suggest in black and white the notion that fat is bad regardless of the nature of the animal and its ecosystem, “fit manufacturing” is more appropriate. Just as there is no “best” or finish line in lean operations, we see no “perfect” creatures, only the “fittest” or most well-adapted to the particular environment. As in biology, so in business.

Lean systems should not be implemented blindly or in ways that lack risk management. There are plenty of human, market and environmental factors to consider. The FMEA (failure modes and effects analysis) is a wonderful tool, but ironically it is seldom applied to the implementation of lean itself. Traditional change management attempts similar things but often without the rigor. Whether it is the steering committee that oversees and governs the implementation of major systems such as lean operations or disaster management at a national level, adequate planning is a must. Perhaps this too must wait for lean thinkers to enter public service.

Fitter means more fit, not necessarily more lean. There is no way to be “too lean” and be fit. If we are emaciated we are no longer fit. We also need a certain amount of fat within any system to survive those natural disasters that are survivable. This lesson should be learned and applied more widely. Placed in an FMEA, the volcanic eruption may not justify a back up transport system from the point of view of frequency, though from the point of view of severity of impact it certainly may. I have friends in Europe who didn’t make it home last week. Some took ferries home because they were stranded in one part of the Continent without clear air space. This would have been a good time for enterprising dirigible drivers to make a quick Euro and get on the map as the redundant air travel channel of choice. Perhaps next eruption.


  1. Daniel Markovitz

    April 22, 2010 - 5:55 am

    Great post, Jon. One of your best. I love the notion that when a knowledge worker is idle, it may be a sign of a healthy redundancy.

  2. Jon Miller

    April 22, 2010 - 11:40 am

    Thanks Dan
    We have to be careful how we phrase that!
    We don’t want to be on record as encouraging idleness.
    A physically idle knowledge worker may still be mentally active. And we could even argue that the napping knowledge worker is using their subconscious to solve a problem. Here again we can learn from biology…

  3. sharma

    May 11, 2010 - 2:32 am

    Dear Jon,
    Nice post. I differ with voices that cry out “A-ha! I told you just in time doesn’t work!” Turn this question around, and just think of the manufacturers who have piled up finished inventory in a non lean method, and are not able to ship it!
    With due respect, I also pity “Alex Blanton, an analyst at Ingalls and Snyder who has covered the U.S. industrial space for four decades”. If only he had spent some months out of those 4 decades understanding TPS!
    “His” darwin anology does not cover the continual improvement in homo-sapiens from apes to humans.
    He also misses that different parts can also have different problems.

  4. Joseph

    May 17, 2010 - 2:08 pm

    Jon. The Tibetan Monks sit and debate a subject for hundreds of years. At the end of one of these debates they came up with the futility of human endeavour. At the end of everything you die so why do anything.
    I like the reference to the FMEA. I did my first one 30 years ago. It is a very under used tool. It gets the experience of people along with the work history down on paper. Without this record when people retire their experience is lost. A new employee can just spend a few days reading the FMEA and they have the history of the component.
    LEAN should be driven by TOTAL COST. If the answer meets that criteria then it should have a chance of flying. PDCA. If you are suggesting that every decision takes account of Chaos Theory we would never have moved out of the caves. We might get hit by a bolt of lightening.
    We all know that going LEAN lowers the water level exposing the rocks.
    I hope that you are not making a parallel with banks and too big to fail. Theirs was not a chance occurrence but Lemmings running as fast as they can over the edge of a cliff. If the experts in the financial markets had built in redundancy we may not have had the recent crash.
    If Fat is to carry you over times when you have no food then why are many Americans fat and Etheopians thin. There must be a parameter that we are not aware of. In DOE we may have an ABCDE FAT…. Interaction we should do a full Anova.
    As a side note. “If a tree falls down in the forest and there is no body around does it make any sound.”
    The emerging countries have got enough lead on the west with their work ethic we do not need to cut our own throats.
    Have a nice day.