The five whys is an effective tool in helping you to move your customer down the ladder of abstraction. The five whys is a simple approach for exploring root causes and instilling a "find the root cause, not the symptom" mentality. Invented by Japanese industrialist Sakichi Toyoda, the idea is to keep asking "why?" until the root cause is arrived at. The number five is a general guideline for the number of whys required to reach the root cause level, but asking "why?" five times versus three, four, or six times is not a rigid requirement.

Of course, we don't want to just keep asking the customer "why, why, why" for fear we will sound like a three-year-old child. Instead, we can find other ways to continue to drive down from the stock answer by peeling away layers of information until we get to the valuable insights about the customer's problem or unarticulated need by asking things such as "Can you tell me more?" or "Why is that?" You can also use the customer's last answer to probe a little deeper: "You said that the product was difficult to learn, and this is because the customer interface is poor. Can you describe ways in which the menu interface is poor?"

Ultimately, the intent of the five whys is to get to a level where you get specific, actionable input that you can use in developing product features and requirements. By doing this, you will establish and be able to focus on the root problem your customers are trying to solve.

An example, as shown in Figure 6.3, from DMAIC tools website, shows how the five whys can help uncover a customer problem where the wrong item was shipped to a customer:

Figure 6.3