Tips for Lean Managers

I’ll Take My Lean with Water, On the Rocks

By Jon Miller Updated on May 19th, 2017

As an archaeology and ancient history buff it’s always exciting when someone discovers the ruins of a lost city. More so when the lost city is found off the coast and under a few meters of water. There is a great deal of history we have yet to uncover. Yet unless we learn how to drain oceans with extreme local precision or unless see a snap ice age, we won’t be walking through those ruins without a wetsuit any time soon, which is a pity.
My day job involves much draining of water to expose what lies below. No, I am not a water disaster recovery specialist, I am a teacher of the Toyota Production System.

There are few metaphors more potent in the lean lexicon than the classic “rocks and water” illustrated below.Inventory is a symptom of managing production and logistics by “push” which means making or moving goods and services without a clear signal from the customer or downstream process. The result is increased costs, lengthened lead-times as queues and Little’s Law take effect, and worst of all the obscuring of problems that make us choose a push system. Lowering the metaphorical water (inventory) makes the problems visible, which in turn allows us to address the problems and to design a more streamlined and responsive production and logistics system that is based on a pull: only making or moving goods and services with a clear customer signal.

This same metaphor or the rocks and the water can also apply at many other levels and in diverse situations. For example we can say that the lean methods, tools and techniques such as 5S, kanban, cellular manufacturing, andon lamps, TPM, standard work and so forth are what lie above the water within a company attempting to implement lean practices. What lies below the water line are those invisible behaviors, strategies, leadership assumptions and beliefs, and unwritten “how we do things” that make up the culture of an organization. Like many ill-fated ships navigating around the tip but crashing on the invisible bulk of icebergs, lean implementations fail when we fail to look under the water and address these behaviors and mindsets.
That said, we need to remember that lean tools and techniques are the principles and philosophies put into concrete and visible practice. There is no separation between mindset, behaviors and tools. Yet there has been a trend to de-emphasize the importance of lean processes, lean tools and lean methods and lean techniques in favor of the softer side of lean, the mindsets and behaviors. These are important but those who advocate this approach are invited to first gain a deep first-hand understanding of the tools themselves, and to be quick to take the leaders you are teaching out of their comfort zone (office) and out to the gemba, where like the tires in a dry riverbed they will be exposed.

Lean tools not only do the heavy lifting of getting the performance improvement results, lean tools make behaviors more visible by lowering the water level. Take for example 5S. The failure to sustain 5S is a failure of leadership. If the leadership understands the essential connection between sort, straighten, sweep and quality, safety, cost and morale it would be at the top of their daily agenda until excellent 5S was second nature. One piece flow forces us to expose, contain and solve our problems rapidly and this requires not just lean tools but a lean organization structure that drives lean behaviors. The kamishibai is a perfect example of a tool that is designed not so much to check on the adherence of the workers themselves to standard work, but to check on the behaviors and implied mindsets of the leaders who do the checking… We could go on with similar examples of the unity of lean tools, behaviors and mindsets, and I encourage you to do so as a team learning opportunity. This may help answer the important question: what’s hiding under our waters?

Rocks and water. More than just a fine way to take scotch. I should have been an ad man.

Update June 5, 2011

Here is a great article from 2008 by the Lean Enterprise Research Center at Cardiff University titled Staying Lean, Thriving Not Just Surviving. The article makes use of many great visuals, including “the sustainable Lean Iceberg” on page 9. I encourage you to read this article to learn how strategy, leadership, behavior and engagement are critical to going beyond the tools and sustaining Lean.

  1. mulyadi

    July 28, 2009 - 2:49 am

    good article

  2. f

    July 29, 2009 - 2:33 pm

    I was very disappointed to read in the NY Times this weekend that Toyota will close NUMMI. It seems like a major abandonment of their brand and process. Do you have any comment on this? I fear this event will undercut lean efforts by Toyota enthusiasts like ourselves everywhere. Please cheer me up! Thanks!

    • Adam

      February 17, 2021 - 6:49 pm

      Elon took over NUMMI and did fine

  3. Joe Molesky

    July 31, 2009 - 12:53 pm

    If, demand is down, why would Toyota keep a manufacturing facility in order to prove a point? If they do not need the capacity, shut it down. It does not matter how well a facility is run, if customers are not buying they are not buying. Sad but true.

  4. Jon Miller

    July 31, 2009 - 1:17 pm

    Some companies will cut people at the first sign of a drop in sales. Toyota is at the opposite extreme, keeping people as long as possible even at the cost of short-term profit. In the case of NUMMI the departure of GM as a part owner represented an actual and significant increase in fixed costs if Toyota had chosen to hold onto it and take 100% ownership. I am sure it was a difficult decision for them and it is a sad thing for everyone who lost their job.

  5. Olivier

    August 2, 2009 - 2:05 pm

    Good point you have here, management have to go beyond tools, methodologies and indicators. Managing an organization is managing people with their history.

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