QAPP CI · AIAG 8-D SUPPORTING TOOL
5 Why
Explore the causal chain through successive questions, using evidence for each link and avoiding conclusions such as “human error”.
Data and preparation
Problem statement, evidence, process sequence, conditions, changes and cause hypotheses
Practical workflow
- Start from a precise observable effect.
- Ask why it occurred and look for evidence.
- Continue each causal link only when it is supported.
- Separate occurrence cause from escape/detection cause where applicable.
- Test the root cause by elimination, reproduction or other evidence.
What QAPP records
| Problem / baseline | Analysis / action | Verification |
|---|---|---|
| Facts, scope, evidence and context | Hypotheses, causes, owner, action and due date | Result, effectiveness, lessons learned and standard update |
Connection to AIAG
AIAG’s 8-D training explicitly includes 5-WHY among the problem-solving techniques. QAPP uses the tool to generate/test causes inside an evidence-based workflow.
Open official source →Common trap
The diagram or question sequence is not the result. A cause becomes credible only when it is supported by evidence and the corrective action changes the predicted mechanism.