Why it was said

Eric Ries writes this in the opening chapter of The Lean Startup, where he replaces the usual measures of startup progress, features shipped, money raised, with validated learning about what customers actually want.

What it actually means

A startup, in Ries's definition, is an organisation operating under extreme uncertainty, and under uncertainty the scarce thing is not effort but knowledge. The team that discovers fastest what people will pay for, through the build-measure-learn loop run on small tests, will out-build a team with twice the engineers and no idea. The sentence sets speed of learning, not speed of building, as the competitive advantage.

How to use it

1. 1Decide what you need to learn before deciding what to build; then build the smallest thing that teaches it.
2. 2Measure what customers do, not what they say, and put a date on the decision to persevere or pivot.