Progress in manufacturing is measured by the production of high quality goods. The unit of progress for Lean Startups is validated learning-a rigorous method for demonstrating progress when one is embedded in the soil of extreme uncertainty. Once entrepreneurs embrace validated learning, the development process can shrink substantially. When you focus on figuring the right thing to build-the thing customers want and will pay for-you need not spend months waiting for a product beta launch to change the company's direction. Instead, entrepreneurs can adapt their plans incrementally, inch by inch, minute by minute.
Layered on top of these various product development practices, we often hear about the concept of "Lean Startup," which was pioneered by Mary Poppendiecks, Tom Poppendiecks, Eric Reis, Ash Maurya, Marty Cagan, Jeff Patton and many others. Speaking broadly, while Agile methods focus on the "how, when, who and where" of rapidly iterating through features and eliminating waste, Lean methodologies focus much more on product validation; the "what" and "why" of these new features we're building and whether they will be successful.