Applying the spirit of KANBAN

For too many years, lean consultants and amateur leanists (yep, I just made that one up) have pursued kanban for kanban's sake.  You have to admit the gains have been remarkable.  We've seen amazing application of the TOOL.  But, as usual, I have to wonder if we are applying the spirit of kanban.

Before you click away, let me explain what I mean by the spirit of kanban.  Kanban is the stuff that you do to make a pull system work.  You can pull for material at the process level or you can pull a product or service through from process to process.   The communication system is kanban.

To keep this simple, let's just look at the process level material flow that uses kanban to manage the pulling.  When we create kanban, we set the resupply levels based on what the process is consuming (and a couple of other things).  I'd like to think that all of the processes we know and love out there are really stable, but the truth is that they are not.  Because the process is variable, the consumption is variable.  So, you really just take a snapshot and hope that your base number (the demand rate, takt, whatever you label it) is close to being real.  You do your calculations diligently from that point on, but inside you realize that your base number is not great.  You've probably used the the wrong unit of time; in fact, you probably made the unit of time too small, thus accentuating the process variability.

You get your system up and running and the invariable happens: stock out....a blessing!

Now you can do some problem solving, determine the point of cause, the problem statement, etc.

There: that was the spirit of kanban.

Did you miss it?

Kanban caused a problem to surface.  In this short (but realistic) example, the point of cause was clear back upstream in the kanban level calculations.  If you did some direct observation, you probably would have noticed that the process demand was variable.  If you watch it long enough, you might be able to see a smoother demand.  If you watch it even longer, you might be able to see some of the waste that is causing the variability.

Without the problem, there is no improvement.

There is was again: the spirit of kanban.

I hope you saw it that time.

The moral of the story: don't implement a tool for the tool's sake.  Implement a tool to make and sustain continuous improvement.  Oh, and you better be sure your organizational culture is ready for it...

PS: How would you solve the example problem?