Fish-bone Diagram

Fish-bone Diagram is a quality tool that identifies many possible causes for an effect or problem.

It can be used to structure a brainstorming session. It immediately sorts ideas into useful categories, helps teams explore and display the causes contributing to a certain effect or outcome.

It graphically displays the relationship of the causes to the effect and to each other, helping teams identify areas for improvement.
The Fish-bone Diagram is also known as cause and effect diagram or an Ishikawa diagram, for its creator. 

When to Use?

  1. Identifying possible causes for a problem or an outcome.
  2. Categorising brainstorm ideas about problem causes.

How to Use?

  1. Form a team of individuals who have a knowledge of the area under analysis
  1. Agree on a problem statement (effect). Write it at the center-right of the flipchart or whiteboard. Draw a box around it and draw a horizontal arrow running to it.
  2. Brainstorm the major categories of causes of the problem. If this is difficult, use generic headings:
    • Methods
    • Machines (equipment)
    • Manpower (People)
    • Materials
    • Measurement
    • Mother Nature (Environment)
  3. Write the categories of causes as branches from the main arrow.
  4. Brainstorm all the possible causes of the problem.
  5. Ask: “Why does this happen?” As each idea is given, the facilitator writes it as a branch from the appropriate category.
  6. Causes can be written in several places if they relate to several categories.
  7. Tip: Develop the causes by asking “Why?” until you have reached a useful level of detail. 
  8. Write sub–causes branching off the causes. 
  9. When the group runs out of ideas, focus attention to places on the chart where ideas are few.

Materials Needed:

Flipchart or whiteboard and marking pens.


  • Institute for Healthcare Improvement – QI Essentials Toolkit
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Dr. Khalid Abulmajd

Healthcare Quality Consultant

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