To identify all of the possible factors that contribute to a problem, i.e. the "effect."
- Clearly describe the problem, i.e. the "effect," to be diagrammed. (For example: files out of place, too many students in line, or job cost above estimate.)
Draw a box around the effect with an arrow heading to it.
- Identify the major categories of factors that contribute to the problem. This will help the team organize the causes.
Four often-used categories are people, equipment, methods and materials. These categories are only suggestions. The team may use any category that helps them think creatively.
Draw a box around each category with an arrow pointing at the effect arrows.
- Brainstorm the detailed factors that contribute to the problem (i.e. the "effect"). Ask for each factor, "what causes this cause (i.e. factor)?" These are written on the diagram and connected to the appropriate main category with arrows.
- Each cause may have sub-causes, which should be shown on the diagram. Continue to ask "why" in order to identify root causes.
Use the following criteria to evaluate your Fishbone Diagram:
- Is the effect clearly stated? Does it relate to the issue statement?
- Are all potential causes listed?
- Are all causes categorized?
- Do causes actually reflect causes, not solutions?
- Do all causes relate to the issue?
- Is the diagram complete and understandable?
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