Jun Aruga's Blog

Output, activities, memo and etc.

Theory of constraints (TOC) - thinking process

There is a management paradigm Theory of Constraints (TOC) [1] developed originally from hard science by Eliyahu Goldratt.

This time my goal is to clarify the steps for all the stakeholders to find bottlenecks (constraints) to change in a project, and make it actionable.


Here are the mandatory 2 steps I find, when doing it with the stakeholders.

  • "1." List all the undesirable effects (UDEs)
  • "2." Create the current reality tree (CRT) from the UDE list with other entities.

Optionally the following steps help the above 2 steps.

  • "3." Use "evaporating cloud" to fix conflicts when seeing the conflicts.
  • "4." Use "3-cloud method" to find core bottlenecks by picking up 3 UDEs with different categories in the UDE list and finding a high level structure.

Optionally here is the next steps.

  • "5." List the desirable effects (DEs) from the UDE list.
  • "6." Create the future reality tree (FRT) from the DE list with other entities.

The processes to learn the steps

Overwhelmed for the steps? No worry. Let's check each part one by one.

TOC for Education [2] is to apply TOC for kids education. I recommend check this slide [3] at first, when you are first time for TOC. Because it makes you recognize "Oh kids can do it. So, we can do it".

The following tools are in the TOC for Education". The logical branch can be used in the process of creating the current reality tree (CRT). Ambitious target tree can be used in the process of creating future reality tree (FRT), prerequisite tree (PRT) and transition tree (TRT) in my assumption. The trees are to clarity the future strategy.

  • Evaporating Cloud (Cloud)
  • Logical Branch (Branch)
  • Ambitious Target Tree (Ambitious Target)

If you can read Japanese, I recommend the book [4] written by the Japan representative of the Goldratt consulting. I can not find this concept's English book so far.

Next is to understand the steps. The slide [5] and [6] are good for that. Eliyahu Goldratt's book "It's Not Luck" [6] is good to understand the steps with UDE, CRT, DE, FRT, evaporating cloud. If you do not have time, just check the pictures. [8], [9], [10] are good websites for that. If you can read Japanese, the "It's Not Luck" manga version [11] is really good. Thanks for the manga culture in Japan. The book [12] is also really good.

Summarizing it, the following 2 slides are a good start in general.

TOC key concepts

Though it's not required to learn the thinking process and tools such as CRT, to understand TOC's key concepts such as in the [1] - History, his book "The Goal" [13] looks good. The English comic version [14] looks good. I have not read both. If you can read Japanese, the Japanese manga version [15] is really good. I did read the manga version.

The Choice

There are beliefs that connect to the clear thoughts written in his book "The Choice" [16]. He said the book was the most important in his books. I referred a person's blog [17] to write the English beliefs as I only did read the book's Japanese edition. Thanks! The topic of the comfort zone explaining an emotional resistance for the change is also good to know.

  • People are good.
  • Every conflict can be removed.
  • Every situation is simple.
  • Every situation can be substantially improved.
  • Every people can have a meaningful life.