A Guide to Implementing the Theory of Constraints (TOC)





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Current Reality Tree


3 Cloud Method

Future Reality Tree

Negative Branch

Pre-requisite Tree



How Do We Build A Current Reality Tree?

How do we construct a current reality tree?  Well, there is no shortage of good descriptions (1, 2, 3).  However, if you are working with a group of more than a 3-4 people, then Bill Dettmer’s description of the Crawford Slip Method (4, 5) is a highly recommended and very effective adjunct to eliciting the required information to construct the tree.

In a nutshell, we need to develop of list of up to 10 undesirable effects that affect our current reality.  They are written in the present tense.  Let’s limit ourselves to 5 in this simple explanation.

Let’s arrange them on in a line in front of us.

Ask yourself, are any a cause or an effect of another.  If so, we can place the cause at the bottom and the effect at the top.  Let’s do that.

It seems that UDE-1 is a cause of UDE-2 and that UDE-3 and UDE-4 are both an effect of UDE-5.  We can indicate the cause and effect relationship using arrows.

We can read the relationship as “If UDE-1 then UDE-2.”  Or “If UDE-5 then UDE-3,” or “If UDE-5 then UDE-4.”

We can begin to build down from these symptom problems to the deeper underlying causes adding new UDE’s or maybe even neutral effects as we go in order to sufficiently describe our current reality.  Let’s do that.

Notice now that UDE-5 is an effect of an underlying UDE and a neutral effect.  These two entities together are the cause of UDE-5 and this is shown by the used of the ellipse.  We read this as “If cause and if other cause then effect.”

Let’s go down one further step.

Now we have tied the two arms of the current reality tree together with a common core problem.

For completeness let’s add a negative reinforcing loop into this tree.

And finally let’s also consider the case of a core conflict rather than a core problem.

Current reality trees have no “preferred shape,” they just happen as you work back down through the underlying cause and effect to a problem or conflict that seems to account for most of the observed symptoms.

We are now in a position to develop a solution to address the core problem and the resulting symptoms.  The tool for that is the cloud.

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(1) Dettmer, H. W., (1997) Goldratt’s Theory of Constraints: a systems approach to continuous improvement.  ASQC Quality Press, pp 62-119.

(2) Dettmer, H. W., (1998) Breaking the constraints to world class performance.  ASQ Quality Press, pp 69-102.

(3) Scheinkopf, L., (1999) Thinking for a change: putting the TOC thinking processes to use. St Lucie Press/APICS series on constraint management, pp 143-169.

(4) Dettmer, H. W., (2003) Strategic navigation: a systems approach to business strategy.  ASQ Quality Press, pp 91-93 & 215-228.

(5) Dettmer, H. W., (2003) Brainpower networking using the Crawford Slip method.  Trafford Publishing, Inc., 181 pp.

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