Fishbone Diagrams in Board Decisions

Fishbone diagrams, also known as “Ishikawa diagrams”, were conceived by organizational theorist Dr. Kaoru Ishikawa in the 1920’s. Today, they’re used in the analysis phase of SixSigma’s DMAIC problem-solving method. The diagrams focus on identifying the “root cause” of an “effect” (an issue or problem).

Identifying the “Root Cause” of a Problem

To understand fishbone diagrams, it’s important to understand the difference between the “cause” of a problem and the “root cause”. A cause may fuel the continued effects of a problem. A root cause, however, is the reason the problem exists.

While they’re often used to visualize and categorize the root cause of problems related to product design or quality control, Fishbone diagrams can be applied to addressing most problems a board faces. This process for identifying the causes of a problem can yield a variety of benefits, including:

  1. Focusing the brainstorming process and the conversation surrounding potential solutions.
  2. Separating the “symptoms” of a problem from its root cause(s) to identify a long-lasting solution.
  3. Identifying “symptoms” requiring immediate mitigation before the root cause is addressed.
    (Example: If you start a grease fire, put it out before rethinking your deep-frying techniques.)

How it Works

Brainstorming through a fishbone diagram is more effective when a facilitator is chosen to lead the discussion. Having a large writing space on which to draw the diagram is recommended. While not required, diagrams are often drawn from right to left using the following procedure:

  1. The facilitator leads the group in creating a problem statement, which is then written on the board and becomes the diagram’s starting point.
  2. Draw a long horizontal line pointing outward from the problem statement. This forms the “backbone” of the fish.
  3. Identify the major factors or cause categories which likely contribute to the problem and write them on branching off of the backbone (refer to the image on the right). recommends starting with at least four categories.
  4. Identify possible causes which may contribute to the problem (the “effect”) and write them branching off of their respective categories. Some causes may have further “sub-causes” which may require further branching (see image below).
  5. Once all categories, causes, and sub-causes have been identified, the facilitator leads the group in analyzing the results.

Note: The branches can be staggered (lines) or mirrored (arrows) on either side of the backbone.


There are a few strategies for analyzing the diagram to identify root causes. One of the biggest indicators of a root cause is that it appears multiple times throughout the diagram. The group should consider asking a few probing questions:

  • Does the cause contribute to the problem or is it simply a byproduct of it?
  • Would the problem still exist if the cause was addressed?
  • Is the cause damaging enough to be addressed immediately
    regardless of whether or not it’s considered a “root cause”.
  • Is it possible to identify a single root cause?

Find the Cause — Form a Consensus

Once the fishbone diagram has been examined, board members will need to form a consensus on which causes are considered to be the “root causes” of a problem. If more than one root cause exists, the board may need to prioritize the order in which the causes are addressed. This can be done with a vote or other similar consensus method such as the Multivoting Technique or Nominal Group Technique.

We hope our guide to fishbone diagrams gives your board of directors a new way to make more effective decisions. But it’s not the only way we’re helping boards make better decisions. Schedule a demo of Directorpoint’s board management software today to learn more!

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