The Evaporating Cloud (EC) Notation

Why Use Evaporating Clouds (ECs)?

ECs resolve a conflict by stating both sides of the problem and reviewing the underlying assumptions that create the conflict. The one requirement is that both sides share the same goal. If needed, refer to the goals behind the current plan.

ECs allow a precise problem description. They define a problem as a 'Common Objective', two separate 'Needs' and two different 'Wants' that conflict.

ECs are methodically used in TOC thinking processes when defining a Future Reality Tree (FRT). First, FRTs are created by injecting solutions from Current Reality Trees (CRT). Then, those solutions are formulated through ECs.

When to Use ECs

• You have a conflict between two parties or approaches that share the same goal. ECs are designed for situations where both sides agree on the objective but disagree on how to achieve it.
• You want to avoid compromise. Rather than splitting the difference (where both sides lose), ECs help you find a solution that satisfies both needs by challenging the assumptions that create the apparent conflict.
• You need a precise problem definition. A well-constructed EC is a structured problem statement. As Einstein (supposedly) said: spend most of the time defining the problem, and the solution becomes easier.
• You are working through TOC thinking processes. ECs are the standard tool for formulating injections (solutions) that feed into Future Reality Trees.

When NOT to Use ECs

• If the two sides do not share a common goal, an EC cannot be constructed — first find a shared objective at a higher level.
• If you are doing root cause analysis, use a CRT instead.
• If you need to plan how to overcome obstacles on the way to a goal, use a PRT instead.

EC Notation Description

The diagram below describes the Notation.

The Node Types in detail:

Node Type	Description	Is Starting Type / Successor
Common Objective	The shared Objective, valid for both branches of the EC	No / -
Need	The perceived Need	No / Common Objective
Want	The perceived Want	No / Need, And
Conflict	The perceived Conflict, expressed as mutually exclusive wants	No / Want, And
And	Combining two elements that are necessary in combination.	No / All besides Assumptions and Solution
Assumption	Expose the underlying assumptions for the EC	Yes / Conflict, Want, Need
Solution	In order to mark the final solution	No / Need

The Evaporating Cloud uses Necessary Condition, which can be expressed by statements like "To achieve ... we must provide ...".

Background on Evaporating Clouds

Evaporating Clouds are the most controversial and most powerful of the thinking processes. You should 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, there cannot be a situation where an unresolvable conflict occurs. If you do not share the same purpose, a dispute will typically not be resolved. 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 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 their course of action or ideas are incompatible. So group A might think we should do "step 27" in the governance process "Vienna", and group B believes not.
• Whenever a conflict is identified, don't compromise because in a compromise, both sides lose, and (see above) it's optional. 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 weighs 3kg). Goldratt suggests instead looking at what scale is misfunction or if both work and whether the concept of weight is right in this situation. Do whatever is needed but resolve the conflict. The item has only one weight and won't be found by compromises.
• Goldratt's theory is that conflicts occur due to implicit assumptions. If you can identify the underlying assumptions, will you be able to find the flaws in one or both opposing approaches?

Find more information on ECs here.

Try EC Yourself

Create and visualise your own Evaporating Cloud diagram right here in your browser. Edit the VGL (Vithanco Graph Language) text on the left and click "Render" to see your diagram:

Tip: Use Ctrl+Enter (or Cmd+Enter on Mac) to quickly render your graph while editing.

Want to learn more about the VGL syntax? Check out the complete VGL Guide for detailed documentation on creating graphs in text format, including syntax reference and examples for all supported notations.

Example

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.

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