The Five Whys

What is this?
This is an interview technique designed to get to the root cause of behaviors. 

When should I use this?
When you’re interviewing users, try to understand the thoughts and beliefs that drive their behavior. 

More about this...
When interview subjects stay at the surface of issues or focus on their actions, the five whys approach can help get to the root cause of their behaviors. If you’re trying to understand why parents opt their children out of standardized tests, for instance, the five whys approach may reveal that their actions are the result of dissatisfaction about how time is used at school rather than the testing itself.