THEORY OF CONSTRAINTS

asic fundamentals of logic is, that behind any logical connectionthere is an assumption. In our case, most probably it is ahidden assumption.Let's clarify it with an example taken from the Theory of ConstraintsJournal. * Suppose that the objective "A" is to "reach thetop of Mount Everest." Why? It doesn't matter, "because it'sthere." Requirement "B" appears in our diagram (which revolvesaround insufficient money) as: "participants must be expertmountain climbers." It looks logical but the connectionbetween "B" and "A" is based on an unstated assumption. Theassumption that we intend to reach the top of Mount Everest byclimbing. It is enough just to verbalize this assumption and picturesof parachutes and helicopters start to flash in our minds.The Evaporating Clouds technique is based on verbalizing theassumptions hidden behind the arrows, forcing them out andchallenging them. It's enough to invalidate even one of theseassumptions, no matter which one, and the problem collapses,disappears. The previous Mount Everest example probably leftyou with a sour taste in your mouth, as it is too simplistic, unfair.So maybe we should try to use this technique on the batchsize problem. Let's remember that this problem is one in whichmore than 10,000 bright people have invested so much timetrying to solve (to the extent that they have published articlesabout it). Evaporating this problem certainly serves, in morethan one way, as a good illustration of the validity of the EvaporatingClouds method.Examine, for example, the arrow connecting requirement "B"to the objective. The influence of setup cost on cost per unit isthe unstated assumption that was taken when we drew the batchsize problem. It doesn't take long to realize that we have takensetup as a given. In other words, we assumed that the setup costis fixed and cannot be reduced. What do we call the method thatso viciously attacks this assumption? We call it JIT. JIT hasproven that just the realization (that setup is not fixed) is almostenough to enable us to achieve (in a relatively small period of* Volume 1, Number 2, Article 1.49