Reader question: Goal Tree vs. Current Reality Tree

Here is a reader’s question: I have difficulty seeing the difference between the Goal Tree and the  Current Reality Tree (CRT). With these two trees we assess the process. What are the main differences between the two?

The Goal Tree and Current Reality Tree (CRT) have nothing in common. They are not even meant to care about processes but about the system as a whole. Neither the Goal Tree nor the CRT are process maps.

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A Goal Tree lists all Necessary Conditions to achieve a Goal, which is not yet achieved, so it is about the future.

The CRT describes why the Goal is not yet achieved in the current state. It starts with identified Undesirable Effects (undesirable for the system as a whole) and drills down to the few critical root causes.

A Goal Tree is built from top-to-bottom with necessity logic while the Current Reality Tree (CRT) is built from top-to-bottom using sufficiency logic. This building top-to-bottom is maybe the sole commonality between the two.

The name Current Reality Tree is somewhat misleading because the CRT is limited to the description of the negative outcomes. It does not describe all the Current Reality. This is saving a lot of unnecessary analysis as well as a warning to not mess with what is currently producing Desired Effects!

What could have caused some confusion to my reader is the fact that a Goal Tree is a benchmark against which to measure the gaps in current reality.

When doing this I use a 3-color code to indicate each Necessary Conditions status. I assess the current condition of the system with the Goal Tree as benchmark. The first autumnal-colored tree should be kept as is as a snapshot of the situation at the beginning. Distinct trees are used later to monitor the progress of ‘greening’ the tree, i.e. closing the gaps to achieve the Goal.

I hope this helps to understand the differences between a Goal Tree and a Current Reality Tree.

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What is a critical root cause?

A root cause is the beginning of the cause-effect relationship*. Thus when working down the chain of causes and effects from a problem to its cause, a Root Cause Analysis (RCA) meets causes themselves being effects of some underlying causes and so on, down to the root cause from which everything about the problem originated.

According to wikipedia, a root cause “is an initiating cause of either a condition or a causal chain that leads to an outcome or effect of interest. Commonly, root cause is used to describe the depth in the causal chain where an intervention could reasonably be implemented to improve performance or prevent an undesirable outcome.” https://en.wikipedia.org/wiki/Root_cause

In “The Logical Thinking Process, A Systems Approach to Complex Problem Solving”, my mentor and friend Bill Dettmer defines a root cause as:

  • *The beginning of the cause-effect relationship
  • The lowest cause in the chain before passing outside the sphere of influence – the most basic thing one can do something about
  • The first cause beyond the sphere of influence, where someone can’t personally do anything about

In the context of the Logical Thinking Process (LTP) and more specifically when working with Current Reality Trees (CRT), a root cause is an entity with arrows coming out but no arrow going in. In this context a root cause is not necessarily something negative.

So far for the root cause, but what is a critical root cause?

Critical root cause

According to Dettmer, a root cause can be a historical event of the past or a fact of life nobody can do anything about. A root cause can also be out of the sphere of influence to change. Therefore, in order to solve problems and remove Undesirable Effects (UDEs), the problem solvers must search for critical root causes, which are defined as:

A policy, practice or prevalent behavior that constitute the lowest level of causality in existing reality lying within someone’s sphere of influence to change. (p108).


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What are Undesirable Effects?

Undesirable Effects (UDEs) in the Thinking Processes lingo are effects undesirable in/for a system, a process or its stakeholders and clients. UDEs are hindrances to better throughput or performance, limiting the system’s throughput or performance at large. UDEs can be obvious problems or malfunctions.

UDEs are generally well-known by people they concern, thus these people can express and list them easily. What is not so easy is to identify the root cause of all evil.

Theory of Constraints assumes that most Undesirable Effects are the visible effects of a unique or a small number of root causes, the constraints; If the constraint can be identified and eliminated, all related UDEs will disappear. Therefore it is meaningful to focus all energy and limited resources to identify and eliminate* the constraint.

*When the constraint is a physical bottleneck, eliminating may not be possible. We speak about “elevating” the constraint in this case, meaning better using the available limited capacity and/or recovering wasted capacity and/or gaining additional capacity.

UDEs are described in a manner such as: “what causes us the more trouble is..”

UDEs are stated in full sentences in present tense and written in rounded square boxes. UDEs are the “leafs” of a Current Reality Tree, which describes all UDEs and their relationships, down to a common critical root cause or more likely a small number of critical root causes.


More about so-called “problems” and UDEs: Redefining “problem” (with Goal in mind)


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What is a Current Reality Tree?

The Current Reality Tree (CRT) is one of the Theory of Constraints (ToC) Thinking Processes (TP) tools. A CRT is built on Undesirable Effects (UDEs) linked by logical cause-effect-cause relationship called “sufficiency”. Sufficiency logic relationship is in the form of “if A is true then B is true”, or “if A exists, then B exists”.

A newer, more complete post about CRT is available >here<

UDEs are written in round squared boxes and arrows depict the relationship. The linkage between UDEs makes a shape of a tree, the root cause being, as the name tells, the bottom-most cause.

Click here to read What are Undesirable Effects

ToC assumed (still does?) that most Undesirable Effects are the visible effects of a unique or a small number of critical root causes*, the constraints. If the constraint can be identified and eliminated, all related UDEs will disappear. Therefore it is meaningful to focus all energy and limited resources to identify and elevate the constraint.

*Read “What is a critical root cause?”

A constraint is a limiting factor that hinders the system to deliver more value.

Read more about >root causes<


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