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?
- Identifying possible causes for a problem or an outcome.
- Categorising brainstorm ideas about problem causes.
How to Use?
- Form a team of individuals who have a knowledge of the area under analysis
- 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.
- Brainstorm the major categories of causes of the problem. If this is difficult, use generic headings:
- Machines (equipment)
- Manpower (People)
- Mother Nature (Environment)
- Write the categories of causes as branches from the main arrow.
- Brainstorm all the possible causes of the problem.
- Ask: “Why does this happen?” As each idea is given, the facilitator writes it as a branch from the appropriate category.
- Causes can be written in several places if they relate to several categories.
- Tip: Develop the causes by asking “Why?” until you have reached a useful level of detail.
- Write sub–causes branching off the causes.
- When the group runs out of ideas, focus attention to places on the chart where ideas are few.
Flipchart or whiteboard and marking pens.
- Institute for Healthcare Improvement – QI Essentials Toolkit