It’s one of the most powerful tools a designer has yet, just asking why isn’t enough but asking “Why?” My science teacher from High-School taught me this technique and over the years it's come in handy.

Sakichi Toyoda

The Five Why’s is an iterative questioning technique use to explore the cause-and-effect relationships underlying a particular problem.

Formally the technique was first developed by Sakichi Toyoda and played an important part in the evolution of Toyota’s manufacturing methodologies.

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What makes this method so special is the simplicity and childlike nature.Pulling this out of the toolbox during interviews. Asking horizontal questions will not prove helpful — it’s all about going deep.

It’s simple, starting with a broad question, ask the person being interview “why?” after every answer but only doing so five times. At the end, things will come into focus.

The Materials Needed

+ Post-It Notes
+ Markers / Pens
+ Whiteboard / Blank Wall

How to Do It

Step 1:
Start by asking the other party a broad question.

Step 2: 
Ask the team to individually write down why that is happening.

Step 3: 
Form a new problem from the answers the team gave.

Step 4: 
Repeat steps 2 and 3 four more times or as much as necessary.

Final Step: 
Analyze the results and form relationships between answers.