The goal of a startup is to figure out the right thing to build — the thing customers want and will pay for — as quickly as possible. - Eric Ries

This is true startup productivity: systematically figuring out the right things to build.

Startups struggle to see their work-in-progress inventory. When factories have excess WIP, it literally piles up on the factory floor. Because most startup work is intangible, it’s not nearly as visible. For example, all the work that goes into designing the minimum viable product is — until the moment that product is shipped — just WIP inventory. Incomplete designs, not-yet-validated assumptions, and most business plans are WIP. Almost every Lean Startup technique we’ve discussed so far works its magic in two ways: by converting push methods to pull and reducing batch size. Both have the net effect of reducing WIP.

This is one of the most important lessons of the scientific method: if you cannot fail, you cannot learn.

Most of the time customers don’t know what they want in advance.)