Five Whys

The Five Whys is a user research and root cause analysis technique that helps identify the underlying reason behind a user behavior or problem by asking why five times. It is often used in UX research, usability testing, and post-mortem processes to dig beyond surface-level observations.

This method was originally designed by Sakichi Toyoda and is widely used in lean manufacturing and Six Sigma. In UX, it provides insights into user motivation, pain points, and systemic design flaws.

Example

Suppose a user quits onboarding midway through a mobile app setup process. The Five Whys technique might look like this:

1. Why did the user leave the onboarding?
   Because it was taking too long.

2. Why was it taking too long?
   Because there were too many steps.

3. Why were there too many steps?
   Because we ask for lots of user info upfront.

4. Why do we ask for that info upfront?
   Because we thought it was necessary to personalize the experience.

5. Why did we think it was necessary?
   Because we didn’t test if users are willing to provide that much data early on.

Each why peels back a layer of assumptions and leads to actionable insights (root cause).

Best Practices

Here are some best practices for using The Five Whys efficiently:

• Use in user interviews, usability tests, or retrospectives.
• Don’t rigidly stick to five, the point is to go deep enough to uncover the root cause.
• Avoid leading questions; keep each why open-ended.
• Document the process for stakeholder visibility.

When to Use

The Five Whys is best suited for:

• Understanding user behavior anomalies
• Investigating high drop-off points
• Reflecting on failed feature adoption
• Supporting other qualitative methods like affinity mapping