The Evaporating Cloud (EC) Domain

Why using Evaporating Clouds? 

EC is used to resolve a conflict by stating both sides of the problem and review the underlying assumptions that create the conflict. Please note that the one requirement of this is that both sides share the same goal. If needed refer to goals behind the current goal.  

ECs allow a precise Problem description. ECs define a problem as a ‘Common Objective’, two separate ‘Needs’ and two separate ‘Wants’ which are in conflict to each other. 

The Evaporating Cloud when Domain Added

Use ECs whenever you have a problem.

ECs are methodically used as part of TOC thinking processes during the definition of a Future Reality Tree (FTRs). FTRs are created by injecting solutions from Current Reality Trees (CRT). Those solutions are formulated through ECs.

Example EC

Goldratt developed TOC based on production inefficiencies. One of his most often used examples is batch sizes and the perceived conflict between cost saving large batch sizes and throughput improving small batch sizes. The resulting EC with some false assumptions is shown below. 

Goldratt’s EC example

These assumptions are more easy to find when the diagram is verbalised, by stating each connection even aloud by constructing “In order to …. we must …”. So, the assumptions here are violating the phrase “In order to reduce setup cost per unit we must run large batches.” Notice the wording “we must”. It invites critics.

EC Domain Description

The diagram below describes the domain. 

The EC Domain Model

The Node Types in detail:

Node TypeDescriptionIs Starting Type / Successor
Common ObjectiveThe shared Objective,valid for both branches of the ECNo / –
NeedThe perceived NeedNo / Common Objective
WantThe perceived WantNo / Need, And 
ConflictThe perceived Conflict, expressed as mutually exclusive wantsNo / Want, And
AndCombining two elements that are necessary in combination.No / All besides Assumptions and Solution
AssumptionExpose the underlaying assumptions for the ECYes / Conflict, Want, Need
SolutionIn order to mark the final solutionNo / Need

The Evaporating Cloud uses Necessary Condition, which can be expressed by statements like “In order to achieve … we must provide …”. 

Background on Evaporating Clouds

The Evaporating is the maybe the most controversial and/or most powerful of the thinking processes. I suggest that you listen to the audio recording of Eli Goldratt in Beyond the Goal. He explains his thinking and the background. My understanding of the EC goes along these lines:

  • As long as two people/groups have the same goal can there not be a situation where an unresolvable conflict occurs. If you do not share the same goal then a conflict will normally not be resolvable. However in most cases it will be possible to find a shared goal if you look at the goals beyond the goal. So, instead of “Marketing needs a budget of XUSD”, you go to the next level and agree on that you want the best for the Marketing department (the budget was only a way to achieve this goal), or even what is the best for the company as a whole. 
  • A conflict in this sense is a situation where two people/groups think that their course of action or there ideas are not compatible. So group A might think we should do “step 27” in governance process “Vienna” and group B thinks not. 
  • Whenever a conflict is identified don’t compromise because in a compromise both sides loose and (see above) it’s not needed. It would be like having two scales, with varying measures for the same item, and you start compromising (4kg or 2kg? Let’s say it weights 3kg). Goldratt suggests to rather look at what scale is misfunction or if both work whether the concept of weight is the right concept in this situation. Do whatever is needed but resolve the conflict. The item has only one weight and it won’t be found by compromises.
  • Goldratt’s theory is that conflicts occur due to implicit assumptions. If you are able to identify the underlying assumptions will you be able to find the flaws in one or both opposing approaches.

From my perspective, I see a ECs following Einstein’s (supposed?) approach to fixing a problem in one hour:  spend most time (first 55 minutes) on defining the problem, then use the rest on solving the issue. Now, this might be extreme time distribution, and the quote most likely doesn’t even come from Einstein, but I believe the idea to be correct. Define the problem first and do it well, any solution will be much easier. And that is ultimately what one does with ECs. A well constructed EC is a precise problem description. Tried if for yourself. 

Find more information on ECs here.