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5 Whys

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Ask "why" five times to find the root cause.

The Technique

1. Start with the problem.
2. Ask why it happened.
3. Take the answer and ask why again.
4. Repeat five times (or until you hit a root cause).
5. Fix there, not at the symptom.

Example

• The site is down.
• Why? The database is overloaded.
• Why? A query got slow after a schema change.
• Why? The migration didn't add the needed index.
• Why? The review didn't catch it.
• Why? We have no migration review checklist.

Fix: migration checklist. Not just restart the database.

Why It Matters

• Teams fix symptoms because they're visible. Root causes hide.
• Without root-cause analysis, the same bug comes back.

The Trap

• Five whys isn't magic — sometimes you need three, sometimes ten.
• It chases single causes. Complex failures have many. Pair with other tools.
• Don't turn it into blame. Focus on systems.

Related

• Hold Regular Retrospectives
• Correlation vs Causation
• First Principles Thinking

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