💡 Why This Tool Matters
When a problem has multiple possible causes across different categories, teams tend to fixate on the most obvious one — usually 'someone made a mistake.' The Fishbone forces you to systematically check 6 categories (the 6 Ms) so no stone is left unturned. Use it before the 5 Whys: Fishbone gives you breadth, then 5 Whys gives you depth on the top 2-3 suspects.
⚡ Facilitator Pro Tip
Give every team member 3 sticky dots for multi-voting after brainstorming. Have them vote on the most likely root causes. The top 2-3 become your 5 Whys targets. This prevents the loudest voice from dominating.
1 Context
2 The Fish Head — Effect / Problem
Write the problem on the right side of your whiteboard. This is the "head" of the fish. Be specific and measurable.
3 The 6 Bones — Brainstorm Causes by Category
Work through each category with your team. Don't evaluate yet — just capture. The categories prevent tunnel vision.
Man (People)
Training? Experience? Fatigue? Staffing? Shift differences?
Machine (Equipment)
Calibration? Wear? Maintenance? Age? Settings?
Method (Process)
Standard work? Sequence? SOP clarity? Steps skipped?
Material
Supplier variation? Wrong spec? Storage? Incoming quality?
Measurement
Gauge accuracy? Right metric? Sampling plan? Frequency?
Environment
Temperature? Humidity? Lighting? Noise? Vibration?
4 Prioritize & Next Steps
Circle the top 2-3 most likely causes. These become your 5 Whys targets or verification investigations.
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