Why you cannot use tentative language in a logic tree

I once happen to see a Current Reality Tree cluttered with “coulds” and “shoulds”. Conditional or tentative language cannot be used with logic trees and here is why.

Cause-and-effect (sufficiency logic)

The Logical Thinking Process logic trees use either sufficiency or necessity logic. Sufficiency or cause-and-effect relationship states that a cause, if it exists, is sufficient by itself for the effect to happen. Using conditionals like should or could violates the sufficiency principle as it suggests that the cause is not always producing the effect.

The Current Reality Tree (CRT), Future Reality Tree (FRT) and Transition Tree (TT) are built on sufficiency logic and therefore cannot hold any entity with shoulds or coulds.

If a should or could is found in such a tree, the scrutinizer must raise a “cause insufficiency reservation“. The statement must then be corrected, for example by adding one or more additional cause(s) combining to the first one with a logical AND connector. If this combination is valid, the sufficiency relationship is restored and should or could is removed as the effect is now guaranteed to happen.

If no additional causes can combine to the first one, the cause-and-effect relationship is probably only assumed or false. Anyway no should or could can be left in a logically sound tree.

Using present tense

The entities – the building blocks of the logic trees holding the statements – must be expressed in present tense.

Using present tense is natural in a Current Reality Tree (CRT) as it is the description of the actual situation, the cause-and-effects relationships that exist right now.

The use of present tense in Future Reality Trees (FRT) is highly recommended even so these future situations and the Desirable Effects do not yet exist. Present tense helps to project oneself and the audience into the future and visualize the situation as it were already improved (Scheinkopf, “Thinking for a change, putting the TOC Thinking Processes to use”, p119). Dettmer also recommends to use positive wording (Dettmer, The Logical Thinking Process, p244).

This applies to entities in a CRT, a FRT and in a Prerequisite Tree (PRT) which are verbalized in full sentences.

What about necessity-based logic?

Can necessity logic based tree use conditional/ tentative language?

The Goal Tree (GT), the Evaporating Cloud (EC) and Prerequisite Tree (PRT) are built on necessity logic. They describe the chains of enabling conditions that are required to achieve a goal or an objective. Without the enabling conditions, the objective cannot be attained. Conversely, with the enabling, necessary conditions fulfilled, the objective will not automatically be achieved; additional action is required.

As the Desired Effect is not guaranteed to happen even so all necessary conditions are fulfilled, the use of conditional / tentative language seems legit. Practitioners would not use it though.

First because we need to demonstrate positivity about a desirable change and help the audience to mentally visualize the future where things happen and produce the desired outcome.

Second because we need to give confidence and demonstrate our own trust in the proposed solution. No audience would be thrilled hearing that this solution “may”, “should” or “could” produce the desired result. No decision maker would give his/her go for a change program or a solution implementation which is not certain to produce the expected result.

The use of conditional / tentative language would only raise concern about the feasibility of the proposed solution and appear as a lack of confidence of its promoters.

Wrapping up

Tentative language is recommended in academic writing, not at all with logic trees.

Using tentative language is recommended in academic writing and scientific research in order to leave room for alternatives, later corrections, etc. unless there is solid evidence backing up a statement. Therefore the use of verbs like “appear, suggest, indicate,…”, modals “may, might, can, could, will, would” and adverbs like “possibly, probably, likely…” are recommended.

But when building or presenting logic trees, absolute certainty is required in order to demonstrate robustness of the analysis and the confidence in the conclusions. If a logic tree is built on the canonical logic rules (we’ll consider the use of present tense as a canonical logic rule), has been scrutinized and cleared of all reservations, it is robust and tentative language is no option.


The author, Chris HOHMANN

The author, Chris HOHMANN

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Why is the Logical Thinking Process so hard to sell?

This is probably the greatest frustration for Logical Thinking Process (LTP) fans: why don’t more people get interested in? Why is the Logical Thinking Process so hard to sell?

Please understand “sell” with the quotation marks, I mean promote, advertise, grow the community, attract participants to seminars and courses altogether.

This post is a reflection of mine and an invitation to other LTP savvy and practitioners to share (please use comments) their analysis and thoughts.

The first reason is the weird sounding proposal to learn how to think. I got this reply of course.

Most people are convinced they are able to thinking in a logical way and don’t see the point learning anything about it. Those knowledgeable about the Logical Thinking Process changed their minds acknowledging they believed they were thinking logically until they went through the humbling experience of the LTP.

Make a clear statement that is both rationally sound and without any ambiguity is one example of the “thinking qualities” so many believe to master naturally but don’t.

Guiding an audience through a chain of causes-and-effects with rock-solid logic and in a crystal clear way is another “gift” commonly thought innate.

From what I’ve seen, everybody going through a Logical Thinking Process training course gets a lesson, regardless of how brilliant a speaker the person already was.

The second reason is maybe the jargon. Theory of Constraints (ToC) is full of jargon, metaphors and poetic names that do not help getting into it without a true motivation.

Other business philosophies and methodologies have their own lingo. Lean for instance “requires” to accept Japanese words without being a serious obstacle for its spreading.

The difference I see between Lean’s Japanese words and ToC jargon is that Japanese words are accepted because most people understand them through their translation / transliteration only. To them, those words have no other meanings that can be misleading.

In the Logical Thinking Process, “Evaporating Cloud” most people (with sufficient command in English of course) try to understand the literal sense in the context but can’t.

The Evaporating Cloud makes sense once the metaphor is decoded. It would have been so much easier to call it a Conflict Resolution Diagram (a proposed and sometimes used alternate name), which it really is, first hand.

Explanation about the sticking to the Evaporating Cloud can be read in Lisa Scheinkopf’s book “Thinking for a Change: Putting the TOC Thinking Processes to Use

Besides poetry and metaphors, acronyms are just as numerous. Take “POOGI” that stands for Process Of OnGoing Improvement in ToC’s lingo. The already popular “Continuous Improvement” was obviously not good enough and led to craft a weird-sounding new acronym, requiring more explanations and learning.

Even some ToC and/or Logical Thinking Process aficionados don’t like all the jargon, it is now the language of the ToC community and its mastery the price to pay for any new comer.

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The Logical Thinking Process dynamics

In this short excerpt of the June 2015 training course, Bill Dettmer shows the links between the Logical Thinking Process tools.

The first link is from the Goal Tree to the Current Reality Tree (CRT). As long as the Goal is not achieved, the not-achieving Goal stated in the Goal Tree and the not-achieved Critical Success Factors (CSFs), which are Undesirable Effects, are inputs to the Current Reality Tree.

Next is the link between CRT and Evaporating Cloud (EC). A critical root cause from the CRT is very likely to be one of the conflicting entities of an Evaporating Cloud. The Goal Tree may also provide inputs to the EC.

An injection to dissolve the conflict in the EC is an input to the Future Reality Tree (FRT) and the desired outcome are the Goal and CSFs, turned into the FRT’s Desirable Effects, closing the loop and making the Goal Tree the key player of the whole Logical Thinking Process.


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Logical Thinking Process

LTPThe Logical Thinking Process refers to the work of William (Bill) Dettmer summarized in the book of the same title. The Logical Thinking Process (LTP) is a one to six steps* process using sound logic and a set of tools (or processes) to provide executives and system managers an effective method for designing organizational strategy, planning its deployment, evaluating its effectiveness, and making corrections as needed in the shortest possible time.

Bill Dettmer & Chris Hohmann

Bill Dettmer & Chris Hohmann

*the number of steps required or used may vary by necessity or choice/experience of the practitioners

It starts with the Goal statement, the Vision or what the Lean community refers to as “True North”. The Goal can be set only by those who created the system, the system owners or those having the responsibility to conduct the organization toward the Goal set by the founders.

The Goal is dependent upon a series of Necessary Conditions, among which some high level terminal outcome are called Critical Success factors. The visual representation from the Goal down to Necessary Conditions forms the Goal Tree.

The Goal Tree is a benchmark but the actual condition of the organization may not be the one required.Thus the Goal Tree gives input to the next tool in the Logical Thinking Process: the Current Reality Tree (CRT).

With the CRT, the organization is assessed or “audited” about gaps between the Goal Tree requirements and the actual condition. Gaps lead to Undesirable Effects or UDEs. These UDEs are the inputs for the next tool: the Future Reality Tree (FRT) in which the UDEs are neutralized with “injections”; causes or conditions not yet existing and designed to turn UDEs into their opposites: Desirable Effects (DEs), without bringing negative side effects.

Logical Thinking Process
Between CRT and FRT is another tool, called Evaporating Cloud (EC) or Conflict Resolution Diagram (CRD). It is specifically used to solve conflicts, like going for small batches wanted by sales and going for big batches wanted by production, for example. Each party has good reasons to demand for what they see as being the best, but usually the conflict is based on false assumptions the EC helps to surface and then “evaporate” the conflict.

The Prerequisite Tree (PRT) is the next tool of the LTP. It is used when stakeholders argue about obstacles to implement the solutions found with the FRT and EC. Every obstacle is then neutralized or by-passed with Intermediate Objectives (IOs), smaller necessary steps and conditions to fulfill in order to bypass the obstacles.

Finally the Transition Tree (TT) is a kind of detailed action plan but still at system level. Actions, combined with the actual reality and the needed condition lead to the desired new reality and closer to the Goal.

Rational, logic, robust

All the Trees and the Cloud are based on logical relationships between their entities, which makes them as well as the whole process unbiased of beliefs, false assumptions, emotional and irrational choices, and filter out irrelevant or unnecessary “nice-to-haves”.

The result, if correctly built, is a very robust and complete roadmap to the next level towards the organization’s goal.

The various tools, especially Goal Tree, Current Reality Tree, Evaporating Cloud and Future Reality Tree may be used as stand-alones or in combination. When rolling out the whole Logical Thinking Process, the work group may stop when the FRT is complete and checked, as they feel no need to get into more details with the next trees.

Jargon!

Don’t be afraid by all the metaphoric jargon, it must be learnt but is not that hard. All the available body of knowledge relies on this jargon and it’s the Theory of Constraints community lingo. No way to do without it, like it or not.

Thinking Processes versus Logical Thinking Process

There is a subtle difference between Thinking Processes – plural – and (Logical) Thinking Process – singular.

  • The Thinking Processes refer to the five tools, four trees and one cloud, from CRT to TT and do generally not include the Goal Tree.
  • The Logical Thinking Process is the process described previously, using the same tools plus the Goal Tree. Bill Dettmer keeps considering the trees and cloud as tools, not as processes and sees only one overall process.

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Conflict Resolution Diagram / Evaporating Cloud

The Conflict Resolution Diagram (CRD), also known as Evaporating Cloud (EC) or simply ‘Cloud’, is a necessity-logic based tool from Theory of ConstraintsThinking Processes.

As the name tells, the Conflict Resolution Diagram is used to surface and resolve conflicts, e.g. dilemmas.

Conflicts, which can be named ‘different points of view’ are not always obvious, thus practitioners will refer to as ‘hidden conflicts’. Indication a hidden conflict exists is stagnation (Dettmer). Two opposite forces pull in opposite directions and nothing goes on.

The CRD is based on two assumptions:

  1. Conflicts (opposition about objectives or opposite points of view, for instance) tend to be settled by compromise. Yet compromising requires making concessions that lead to a solution which isn’t satisfactory for neither side, hence a win-lose or lose-lose situation.
  2. Conflicts are often the result of false assumptions, beliefs or myths which constrain needlessly the organization. As two opposite things cannot be true at the same time, one is necessarily false. If the falseness can be debunked, the conflict disappears (evaporates) and a no-compromise, win-win solution is found.

Resolving the conflict is done by first exposing the two sides’ arguments, second through “injection(s)”; adding something, solution, countermeasure, a “remedy” that didn’t exist in the system.

The structure of a Conflict Resolution Diagram / Evaporating Cloud

A (simple) CRD is made of five entities (round cornered boxes) conventionally named A,B,C,D and D’.

Entity A is the common objective which requires B and C to exist; in order to have A, we must have B and C.

D is a prerequisite to B (in order to have B, we must have D), while D’ is a prerequisite to C.

D and D’ cannot exist or happen simultaneously, like for example attend a meeting in Rome and in the same time attend a conference in Berlin. In this case the conflict would be a dilemma chosing between the two events. D and D’ may not happen simultaneously because available resources do not allow it and the dilemma is about allocation of the scarce resource.

Arrows are symbols of necessity relationship. In the same time the arrows are symbols for underlying assumptions, and as such can be true or false. But the assumptions are usually statements (beliefs) and/or justification for the relationship. The CRD’s purpose is to surface and test these assumptions.

The broken arrow or lightning between D and D’ is the symbol for opposition or conflict.

Surfacing and testing the underlying assumptions and injections

Once the CRD is drawn, participants are asked to verbalize all underlying assumptions under each arrow. If one of the assumption can be proven as false, it is probable that the problem evaporates (we do expect the defenders of the false assumption to give it up as false).

An assumption can also be invalidated by an injection, which are ideas or conditions that render one of the assumptions invalid.

Note: Dettmer recommends not to inject solutions in order not to constrain the injections with reservations about feasibility.


Conflict Resolution Diagram can be used as a stand-alone tool or sequentially after a Current Reality Tree (CRT). In this latter case, the analysis with the CRT helped discover the root cause of all Undesirable Effects (UDEs) usually called problems. This root cause is generally a conflict or dilemma the CRD can ‘evaporate’, thus solve the problems.

Solving a problem with a CRD is a bit more complex than in this brief description and requires some practice.

References

  • Fedurko, Jelena (2011) Behind the Cloud, enhancing logical thinking, TOC strategic solutions
  • Dettmer, H. W., (1997) Goldratt’s Theory of Constraints: a systems approach to continuous improvement. ASQC Quality Press
  • Scheinkopf, L., (1999) Thinking for a change: putting the TOC thinking processes to use. St Lucie Press/APICS

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How deep should a Goal Tree go?

When breaking down the Goal into Critical Success Factors (CSFs) and Necessary Conditions (NCs), the question soon arises: how deep should we dig to build the Goal Tree?

There is no general answer to this question except: as deep as necessary to serve your purpose and as deep as necessary for you to feel comfortable with. Which is not very helpful to beginners.

In order to give more practical advice, let’s consider two cases:

  1. Goal Tree used to (re)define a strategy at executive level, used with the Logical Thinking Process
  2. Goal Tree used at any level as a stand-alone tool, with an action plan

1. Goal Tree used to (re)define a strategy at executive level

Dettmer introduced the Goal Tree as a logically sound and robust benchmark prior to assess the Current Reality and work to solve the problems that hinder the organization achieving its Goal. It starts with the Goal, which is a lighthouse guiding all initiatives and onto which to align all contributions. The Goal Tree is therefore the first logical tree to be built in the process called… Logical Thinking Process.

Logical Thinkng Process

The Goal, purpose or “big picture” is defined by the system owner, the founder(s) or those having delegate power to lead the organization toward its Goal. These top most executives may not want nor have time to be dragged down into each detail of all the Necessary Conditions for the Goal to be achieved.

Therefore they will be highly interested in the answer to the question how deep should a Goal Tree go?

The answer: In order to feed the Current Reality Tree, the Goal, the 3 to 5 Critical Success Factors and the two layers of NCs beneath them are enough. All of them will become entities of the CRT.

Indeed, experience confirms that going this deep is enough. The CRT building methodology helps finding the critical root cause(s) and the links between all these entities. As neither the Goal nor CSFs nor the few high level NCs are achieved yet, the building of the CRT starts by expressing the Undesirable Effects (UDEs), which are deviations from the desired achievement. Logical analysis leads to the Critical Root Cause(s) without needing a complete detailed Goal Tree.

Even it is not required, if someone feels more comfortable with a more detailed Goal Tree and can afford the time building it, let him/her go for it.

2. Goal Tree used at any level as a stand-alone tool

A Goal Tree can be used as a stand-alone tool and one does not need to go through the whole Logical Thinking Process for preparing an action plan. This could be the case of a new activity starting from scratch in which no previous existing state has to be improved. It can also be a project for which all elements are represented in a Goal Tree and the Tree is used to check the completeness of the tasks and Necessary Conditions envisioned. Finally it can be an improvement in a department or organization in which there are no major complex problems to solve, not requiring to go through the whole LTP.

In such cases, how deep should the Goal Tree go?

Well, basically a Goal Tree is not limited, but soon practical limits will surface, starting with the number of CSFs. I keep recommending to limit CSF to five, which are sufficient in most cases.

>Read more about defining CSFs

Soon, the limited number of CSFs will lead to a fair number of first level NCs, followed by an even greater number of level 2 NCs and so forth.

Goal Tree

The number of levels or depth of the tree depend how fast the breakdown reaches the trivia level. In an established business there is no need to describe what is the very essence of it.

For example in manufacturing it is not necessary to set “master milling techniques” or “have expertise in wave soldering” if it’s already part of the daily operations.

It is different when a new manufacturing way is envisioned, as for example manufacturing parts not by cutting material away but adding it, like in 3D printing for example. If these new techniques are not yet known within the company, acquiring them and mastering them may be set as Necessary Conditions.

In general, digging deeper into NCs is meaningless once the NCs do not provide helpful Intermediate Objectives to align contributions anymore.

Being too specific makes the Goal Tree difficult to maintain and giving too many precise requirements to staff reduces the interest in the job as everything seems to be prescribed. Conversely, giving higher level objectives to staff and asking them to work out the plan to achieve them is motivating and helps buy-in as staff gets involved in the project definition.

>Read more about Goal Tree as vehicle for change management

There is no absolute limit nor any general recommendation about depth of Goal Tree, except people must be comfortable with.

Cascading objectives in an organization

When cascading objectives in an organization, my rule of thumb is to try limiting to five or six levels deep: Top management sets the CSFs, head of departments the first and second level of NCs, middle management the next two or three levels of NCs.


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