Eric Ries

To accelerate, Lean Startups need a process that provides a natural feedback loop. When you’re going too fast, you cause more problems. Adaptive processes force you to slow down and invest in preventing the kinds of problems that are currently wasting time. As those preventive efforts pay off, you naturally speed up again.

The alternative is to use a system called the Five Whys to make incremental investments and evolve a startup’s processes gradually. The core idea of Five Whys is to tie investments directly to the prevention of the most problematic symptoms

Repeating “why” five times, like this, can help uncover the root problem and correct it.