The five whys is a technique that doesn’t involve data segmentation, hypothesis testing, regression or other advanced statistical tools, and in many cases can be completed without a data collection plan. By repeatedly asking the question “Why” at least five times, you can peel away the layers of symptoms which can lead to the root cause of a problem.

Here is a simple example of applying the five whys to determine the root cause of a problem. Let’s suppose that you received a large number of customer returns for a particular product. Let’s attack this problem using the five whys:

• Why are the customers returning the product? Answer: 90 percent of the returns are for dents in the control panel.
• Why are there dents in the control panel? Answer: The control panels are inspected as part of the shipping process. Thus, they must be damaged during shipping.
• Why are they damaged in shipment? Answer: Because they are not packed to the packaging
  specification.
• Why are they not being packed per the packaging spec? Answer: Because shipping does not have the packaging spec.
• Why doesn’t shipping have the packaging spec? Answer: Because it is not part of the normal product release process to furnish shipping with any specifications.

Using the five whys in this case revealed that a flaw in the product release process resulted in customers’ returning of a product.