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  • Writer's pictureJ.D. Solomon

Five Ways to More Effectively Facilitate Tree Diagrams

Cat stuck in a tree.  Facilitors communicaiting with finesse never get stuck in a tree (diagram)
Ever seen a cat's skeleton in a tree? Nope, they always come down. Some facilitators get stuck in the proverbial tree and never make it down.

This article discusses five ways to effectively facilitate tree diagrams by conducting pre-session exchanges, asking powerful questions, using exercises that engage, anticipating disruption, and controlling the tempo. The foundations of systems thinking and facilitation apply to tree diagrams because the analysis requires a group to establish the nature of separate and inter-related components.

Facilitation is defined as a structured session(s) in which the meeting leader (the facilitator) guides the participants through a series of predefined steps to arrive at a result that is created, understood, and accepted by all participants." As provided in the definition, the fundamentals of good facilitation are always essential, including having a structure for developing tree diagrams that include predefined steps and a process for arriving at results that are created, understood, and accepted by all participants.

Facilitating Tree Diagrams

A tree diagram is a management tool that depicts the hierarchy of tasks and subtasks needed to complete an objective. The finished diagram bears a resemblance to a tree. (American Society for Quality, 2019).

Having a diagram makes a problem conceptually easier to understand. A tree diagram also is known as a systematic diagram, analytical tree, hierarchy diagram, and tree analysis. While conceptually the diagram eases understanding, facilitators should continually remind themselves that there is nothing easy or simple about bringing a group to common understanding when the title has words like systematic, analytical, or hierarchy.

The following types of fault trees are referenced as relative to this article.

  • Fault trees – typically used in failure analysis

  • Cause-consequence diagram – used in root cause analysis; similar to fault trees

  • Event Trees – used to show a future state and all of the premises that would make it occur

  • Decision Trees – used to graph decisions and their possible outcomes

  • Probability Trees – used to graph decisions, assign probabilities and calculate impacts

  • Influence Diagrams – used to program calculations and create computer models

If you get confused, remember there are two major types of tree diagrams. Backward-looking tree diagrams are normally associated with finding fault or causation. Forward-looking trees are normally associated with future actions or activities. The logic gates, such as “and” meaning all preceding events must happen or an "or" means either of the preceding events can happen, is the same whether looking forward or backward.

The greatest challenge of developing a tree diagram is working through the logic that must tie together the many parts (complexity). An associated challenge is the difficulty in developing the chart visually with a team, regardless of the size of the whiteboard you use or the type of software (including Excel) that you employ.

These are five ways to be more effectively facilitate tree diagrams.

Pre-Session Exchange

In previous articles, in-person discussions, virtual discussions, and online surveys are referenced as viable forms of pre-session exchange. Pre-session exchange should also include discussions with the executive sponsor to confirm their goals, sensitivities, and expected outcomes of the facilitated session.

The pre-session exchange should be used to develop an accurate tree diagram before the facilitated session. One reason is that tree diagrams can take several forms and requires several iterations. Developing the tree diagram from scratch during the session takes too much time, leads to participant frustration, and hurts the facilitator's credibility. A second reason is that using commercially available software prior to the session provides a check that the logic that has been used is correct.

Data is essential for developing a tree diagram in the pre-session exchange. Data and the information related to how it logically tie together are also essential components of developing a pre-session tree diagram. In most cases, the facilitator will need to utilize in-person discussions, virtual discussions, and online research in the pre-session exchange.

Powerful Questions

Great facilitators use imagination phrases like "Think about…", "Imagine…", and "Consider…." There should be a balance between expanding the thinking and avoiding unrealistic speculation when developing event trees, decision trees, and probability trees. Something on the order of the 5th and 95th percentile usually sets a realistic boundary to keep the participants grounded. When doing fault trees, the rule is to stay focused on what has occurred and what may be in the participant's actual experience, and not on something they have heard might have happened or something they saw on social media.

For tree diagrams, choosing a starting point can shape the content of powerful questions. The facilitator may choose one or more starting points: the documented effect (consequence), the starting point, one or more functions, or one or more themes. In the case of functions and themes, the facilitator should consider these as starting in the middle, with the intention of tying together different logic trees from subgroups of specialists. The major takeaway is that the starting point shapes the questions that are asked and how they are asked.

Exercises That Engage

The most engaging exercise when developing a tree diagram is to develop the tree diagram by hand during the actual session. Tree diagrams, especially those generated from software, are visually overwhelming to most people. Plus, each person moves around different places on the diagram to better understand it. Doing it together helps the action stay directed and keeps the participants fully engaged.

Framing the problem is especially important when facilitating the development of a tree diagram. Setting boundary conditions is an engaging operating exercise that gets participants engaged. Many different approaches and tools can be used.

Sticky notes exercises, especially sticky dot exercises, are overworked in facilitated sessions. However, the best format to use sticky notes is in developing tree diagrams because they allow the participants to evolve and pivot their logic in a hands-on manner. Custom sticky notes in the forms of boxes, circles, diamonds, and other shapes can also be obtained affordably.

Anticipate Disruption

All of the previously discussed approaches in other articles to anticipate and mitigate disruption apply. These approaches include well-defined approaches for creating a “parking lot” of contentious issues, establishing a smaller facilitation advisory team, pivoting to breaks, not engaging in arguments, and projecting interactive information onto a board or screen.

One big disruptor is related to disputes in logic. For example, in developing cause-consequence diagrams, many participants will have different opinions on the causation (i.e., different 5 Whys). A different example is related to probability trees, where participants often dispute the reality of certain alternatives or the relative range of probability of occurrence even if they can agree on the alternatives.

The best advice is to capture everything and then sort through it later. Putting everyone’s ideas on the whiteboard or projected screen calms a combative audience while trying to sort out the best solution in front of the entire team only tends to escalate emotions.

Remember that tress diagrams require the most iteration of all of the types of technical facilitation. Regardless of participant availability or scope of services, logic necessarily takes cool heads. Facilitators must be persistently patient.

Controlling the Tempo

Tree diagrams are a journey in logic and require fresh, level-headed minds. Pre-session exchange and the preliminary tree diagram developed through those exchanges are essential efficiently and effectively. Shorter, iterative sessions help minimize fatigue.

Capturing everyone's thoughts and not trying to discount anyone too early is a good approach for minimizing disruption. All of these approaches also help control the tempo.

Having a structured approach is important to any type of facilitation. Tree diagrams are no exception. Participants need to know what they are doing, the sequence they are doing it, how they will know when it is time to stop, and what information will be developed or modified between sessions. A guiding graphic of the process is extremely helpful in controlling the temp.

Performing a sensitivity analysis is also effective in controlling the temp because it shows the progress being made and refreshes the audience. This is especially true in the case of probability trees. It is also true in less obvious ways in fault trees when debating the impact of Boolean logic of "and" our "or" gates. Understanding the sensitivities clarifies the relative impact of one form of logic or argument on another.

Thinking About It

The foundations of systems thinking and facilitation apply to tree diagrams, rich with many parts and the logic that connects them. The five ways to more effectively facilitate tree diagrams enhance a facilitator’s ability to guide the participants through a series of predefined steps to arrive at a result that is created, understood, and accepted by all. Seek to make your tree diagram facilitation better than most, or better yet, above all others.


JD Solomon Inc provides facilitation at the nexus of facilities, infrastructure, and the environment. Contact us for more information about facilitation services ranging from Strategic Plans and Board Retreats to Criticality Analysis, Root Cause Analysis, and Capital Program Development. For more information on JD’s new book or to join the community of technical professionals committed to learning how to get their boss’s boss to understand, visit Communicating with FINESSE or sign-up for updates.


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