Tree Diagrams

Simplifying Complexity

Tree Diagrams - Simplifying Complexity

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Each idea, solution or event has its own "branch."

We might associate tree diagrams with high school math; as simple tools commonly used to calculate probabilities or chart a series of events. However, they can be useful in the workplace too. They can help you analyze options, solve problems, and brainstorm different ideas with your team.

In this article, we'll look at what tree diagrams are, and discuss the many powerful ways you can apply them.

What Is a Tree Diagram?

A tree diagram is a visual depiction of relationships that starts with a central node, or "trunk." This is the problem that needs solving or the idea you are analyzing. Each possible solution or event has its own "branch," which comes off the trunk to the top or bottom right-hand side. Additional decisions, consequences or effects split off from each of these "second layer branches," giving the diagram a tree-like structure.

You can use tree diagrams to break down categories or events into finer and finer levels of detail. This helps simplify complex problems (and their proposed solutions), and makes it easier for you to get an overview of your options.

Figure 1 – Example Tree Diagram

Tree Diagrams


Among other uses, tree diagrams can help you to:

  • Find the root cause of a problem.
  • Outline the steps needed to solve a problem or implement a plan.
  • Identify the true scope of a project.
  • Explain steps or details to others.
  • Brainstorm possible outcomes.

Tree diagrams also help shift your thinking from the "big picture" to the subtleties of an issue. When you first draw the diagram, you look at the issue in its broadest sense. Your focus narrows when you flesh it out, and drill down to the finer detail. This shift in perspective is especially helpful when you're faced with large or particularly complex problems.


Mariella's boss has asked her team to improve its performance by 20 percent. She draws a tree diagram to break the objective down into meaningful sub-goals, so team members can understand exactly what they need to do.

She begins by writing the primary goal first; this is the "trunk" of the diagram.

  1. Improve performance by 20 percent.

Next, she and her team discuss how they can meet this goal. The team creates a new "branch" in the diagram for each idea to help it become more productive.

  1. Cross-train team members.
  2. Get better organized.
  3. Find more customers.

Each of these ideas is broken down further, so team members are clear about what they need to do. So, the group keeps brainstorming, and adds the following additional branches:

  1. Cross-train team members: Job rotation, job shadowing, job sharing.
  2. Get organized: Simplify client filing system, reduce clutter in the office, time-management training.
  3. Find more customers: Increase cold calling, social networking outreach, sponsor community events.

Mariella and her team keep expanding the tree diagram, using the final branches to assign tasks to specific people and to set deadlines. She then puts a printout in the break room to remind everyone what they're working on, and who is responsible for each task.

Types of Tree Diagram

There are many different types of tree diagram, and each has a specific application.

Making Decisions

Decision Trees are a common form of tree diagram. They can help you make the right choice when you're faced with several possible options. With them, you look at each alternative and investigate its potential outcome to determine which one offers the best balance between risk and reward.

There are always consequences when you make a decision. Sometimes they are positive, other times they're not. The Futures Wheel tool uses a type of tree diagram to help you explore them.

You can also use a tree diagram when carrying out an Impact Analysis to identify the possible negative consequences of a proposed change.

Solving Problems

If you're faced with a complex problem, it can be challenging to identify its root cause and come up with an effective solution. Specialist tree diagrams can help you simplify this task.

Cause and Effect Analysis uses "fishbone diagrams," which are effectively horizontal tree diagrams. They enable you to discover the root cause of a problem, identify bottlenecks, and analyze why a particular process isn't working.

Sometimes you'll need to come up with several possible solutions to a problem, and this is when Concept Fans – based on the structure of tree diagrams – are useful. They let you take both a micro and a macro look at your problem, and generate as many options as you need to solve it.

Critical to Quality Trees are similar – they help you identify your customers' needs, and explore ways to meet those needs.

Predicting Behavior

You can use tree diagrams to predict behavior. For example, they're commonly used in game theory to predict how your competitors might react in a given situation, or how a negotiation could play out. In this context, you use "game trees" to chart "players'" every possible move.

Taking Notes

Tree diagrams can be useful for taking notes. For example, Mind Mapping is a useful tool for summarizing information, for consolidating large chunks of information, for making connections, and for creative problem solving. Mind Maps show facts, as well as the overall structure of a subject and the relative importance of individual parts of it.

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How to Create a Tree Diagram

This is a relatively simple task, and there are several ways to do it.

On Paper

To draw a tree diagram by hand, start on the left-hand side of your paper (for a horizontal tree), or at the top (for a vertical tree). Write the problem or issue you're addressing in a square or circle.

Then, drill down to the next level of detail. For example, if you're trying to find the root cause of a problem, think about what could be causing the issue. Draw lines out for each possible cause and label it appropriately.

Once you've brainstormed all the possibilities at this level, look at each idea in turn. Using our problem-solving example, you can then drill down to the next level of detail by asking "What" or "Why" questions. For example, "What do we need to do to make this happen?" or "Why does this happen?"

Using Software

You can draw tree diagrams using packages like Microsoft® Word. There are many free templates that you can download from the Internet, which automate and simplify the process.

You can also download software, like SmartDraw™, or add-ins for Microsoft Excel, such as TreePlan™, to create comprehensive and professional-looking diagrams.

The advantage to using software is that you can share what you create with others easily, and quickly make changes or add more branches. It also allows you to create high quality, professional diagrams, and seamlessly insert them into presentations or reports.

Using Online Apps

There are also web-based applications, such as draw.io™ and Creately™, which help you create and save your tree diagram online. These applications are useful for team collaboration, especially when you're working with a home-based or virtual team.

Key Points

Use tree diagrams to solve problems and make decisions by breaking information down into finer levels of detail. They help you to simplify complex problems, and make it easier for you to visualize all your options. Tree diagrams also help you find the root cause of a problem, break down large goals, and explain steps to others.

To draw a tree diagram, start by writing your problem or issue on the left-hand side of the page; this is the "trunk" of your tree. Next, identify the tasks that you need to complete to accomplish your goal; each should have its own "branch" off the central trunk. Look at them individually, and create further branches until you can't simplify or drill down any further.

Apply This to Your Life

  • Think carefully about any problems or situations you're facing now at work. Draw a tree diagram to brainstorm possible solutions.
  • If you have a decision to make, use a tree diagram to explore your options and identify the consequences of each one.