fishbone-analysis

# Fishbone (Ishikawa) Analysis ## When to use Use fishbone analysis to brainstorm all possible causes of a quality problem **before** running 5-Why. It prevents tunnel vision and ensures no cause category is overlooked. Particularly valuable for complex defects with multiple potential contributing factors. Typical use: 8D D4 brainstorming session, CAPA root cause investigation, initial problem analysis. ## Prerequisites - Problem clearly defined with Is/Is-Not or 5W2H - Cross-functional team (quality, production, engineering at minimum) - Access to the process, machine, or product where defect occurred ## Required Fishbone Checklist ☐ Problem statement defined and agreed before starting — no cause language in the problem statement ☐ All 6M categories addressed — at least one entry per M, or documented justification if a category is not applicable ☐ Brainstorming completed before any evaluation or elimination — do not evaluate while generating ☐ Every cause classified as Confirmed, Probable, or Unlikely using objective evidence — not opinion alone ☐ Confirmed = supported by data or physical evidence; Probable = logical, consistent with Is/Is-Not, not yet confirmed; Unlikely = contradicted by data ☐ Confirmed and Probable causes cross-checked against existing PFMEA failure cause entries before proceeding to 5-Why ☐ Each Confirmed or Probable cause carries forward to its own 5-Why chain ☐ After root cause confirmed: horizontal deployment check — could the same cause exist...