5 Why

asking why until the root cause is found

A simple root cause technique: ask why the problem happened, then why that happened, typically about five times, until the answer is a cause that can be acted on. In an 8D it is applied separately to why the defect occurred and why it escaped.

Calculate it

8D Report: Guided D0 to D8 report with 5W2H, 5 Why, action tables and photos, exported to PDF.

Related terms

• 8D: eight disciplines problem solving
• Ishikawa diagram: fishbone or cause and effect diagram