The Five “Why’s” was originally developed by Sakichi Toyoda of the Toyota corporation in the 1930’s as a method of root cause analysis. It has been adapted since then in several ways such as problem solving and product development. I have adapted it for requirements gathering and have added the follow-up question “How”.
In requirements gathering, too often stakeholders will try to put the “how” before the other questions. Or they’ll work half way through the W’s and insert the How. In my opinion, based on 25 years of experience developing software, the “how” question is not something the stakeholders should decide. That would be like fuel car drivers telling Tesla how to build an electric vehicle. And the “how” question should always come last.
Is there a particular order to the “W” questions? I would say yes. You see, the why questions, in order, establish that the team has thought through all the important elements of an opportunity or problem before proceeding. I have broken down my adapted process in this chart.