Five Whys
Dig past symptoms to find root causes. Ask 'why' five times.
What is it?
The Five Whys is a root-cause analysis technique originally from Toyota's manufacturing process. By asking 'Why?' five times in succession, teams drill past surface-level symptoms to uncover the fundamental cause of a problem.
When to use it
Use Five Whys when a problem keeps recurring, when a usability issue seems obvious but the fix doesn't work, or during post-mortems and retrospectives.
How to do it
State the problem clearly and specifically (e.g., 'Users abandon the checkout at step 3').
Ask 'Why does this happen?' and write the answer.
For each answer, ask 'Why?' again. Repeat 5 times (or until you reach a systemic root cause).
Identify which root cause is actionable and within your control.
Design a countermeasure that addresses the root cause, not just the symptom.
Pro tips
Don't accept vague answers like 'users are confused.' Push deeper: WHY are they confused?
Sometimes you need 3 Whys, sometimes 7. Five is a guideline, not a rule.