Fishbone Diagram

(also called cause/effect diagram, Ishikawa diagram)

What Is It Good For?

This type of diagram can provide a foundation to break down a complex process into manageable factors. You can then generate ideas for data collection and/or solutions. (You may want to use this in conjunction with a Pareto Chart to identify the most important factors or the factors most in need of addressing.)

It is useful to:

• Determine resources
• Link resources with goals
• Determine significant factors to analyze

How Do I Use It?

1. Write the problem on the right side of a flip chart. Draw a large arrow that points toward the problem.
2. Draw arrows indicating the main types of causes or contributing factors and point the arrows toward the central arrow.
3. Brainstorm for specific causes. Attach each specific cause to an appropriate main cause.
4. Break down the causes further by brainstorming for subcauses.

Draw different fishbones for different types of analyses.

 
• Cause/effect.--Several causes probably contribute to one effect. To list and analyze these causes, draw an arrow to the effect. Use this backbone to branch off into major causes. For each cause, ask "Why does this happen?" and "What influences this result?" These answers will provide smaller bones on the major causes for further detail.
• Inertia analysis.--Most situations rest at an equilibrium--forces for change are evenly matched by forces against that change. To analyze this, describe the desired situation and the current state. Then use a fishbone diagram to show all the forces for and against change on either side of the main line. Make the lines thicker, brighter, or longer to show the relative strengths of these forces. Once these are laid out, you can see which forces would be easier to adjust to make the current state closer to the desired one. Pay attention to what you can do--not to the assumed solution(s).

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