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Icologiq Knowledge · Method
5 Whys
A root-cause questioning method that repeatedly asks why a problem occurred to move from visible symptoms toward underlying causes.
Also known as:
Five Whys, 5 Why, Five Why Analysis, 5 Whys Analysis
At a glance
Type
Method
Topic
CAPA & Incidents
Applies to
Cross-industry
Current version
Status
Last reviewed
September 29, 2026
Definition
5 Whys is a root-cause analysis method that starts with a clearly defined problem and repeatedly asks why it occurred. Each answer becomes the basis for the next question, helping an investigation move beyond the immediate symptom toward deeper process, control or organizational causes. The number five is a practical convention rather than a fixed rule: a useful analysis may require fewer or more levels of questioning.
Why it matters
For Quality, QHSE and operational teams, 5 Whys is valuable because it is simple enough to use during incident and CAPA investigations without turning every problem into a large analysis project. It works best when answers are supported by evidence and the team avoids stopping at convenient explanations such as operator error. For complex or multi-factor events, 5 Whys should be combined with broader methods such as a Fishbone Diagram or other structured cause analysis.
A systematic approach for identifying the underlying causes of a problem or event instead of addressing only its immediate symptoms.
Root Cause Analysis
Method
· CAPA & Incidents
A structured process for addressing causes of actual or potential problems through corrective or preventive measures and verifying that actions are effective.
CAPA
Process
· CAPA & Incidents
The structured process for reporting, assessing, investigating, following up and learning from incidents and related events.
Incident Management
Process
· Incident Management
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