The critical first question for any lean transformation is: which activities create value and which are a form of waste? Once you understand this dis… - Eric Ries

which of our efforts are value-creating and which are wasteful?

a new breed of designers is developing brand-new techniques under the banner of Lean User Experience (Lean UX). They recognize that the customer archetype is a hypothesis, not a fact. The customer profile should be considered provisional until the strategy has shown via validated learning that we can serve this type of customer in a sustainable way.

The Five Whys ties the rate of progress to learning, not just execution. Startup teams should go through the Five Whys whenever they encounter any kind of failure, including technical faults, failures to achieve business results, or unexpected changes in customer behavior. Five Whys is a powerful organizational technique. Some of the engineers I have trained to use it believe that you can derive all the other Lean Startup techniques from the Five Whys. Coupled with working in small batches, it provides the foundation a company needs to respond quickly to problems as they appear, without overinvesting or overengineering.

They had “achieved failure” — successfully, faithfully, and rigorously executing a plan that turned out to have been utterly flawed.