We define Experimentation as the implementation of the Lean Startup methodology of testing assumptions and constantly experimenting with controlled risks.

In the Lean Startup model, an experiment is more than just a theoretical inquiry; it is also a first product.

exist to learn how to build a sustainable business. This learning can be validated scientifically by running frequent experiments that allow entrepreneurs to test each element of their vision.

Experimentation is the essence of living a satisfying, productive, fulfilling life. The more you Experiment, the more you learn, and the more you’ll achieve.

A startup is in reality a 'faith-based enterprise' on day one. To turn the vision into reality and the faith into facts (and a profitable company), a startup must test those guesses, or hypotheses, and find out which are correct.

Build-Measure-Learn. The fundamental activity of a startup is to turn ideas into products, measure how customers respond, and then learn whether to pivot or persevere. All successful startup processes should be geared to accelerate that feedback loop.

Should philosophy guide experiments, or should experiments guide philosophy?

From now on, everything you do in this book, and after, should be viewed as an experiment. This has been a profound shift for people who worry that “starting a business” is this big daunting thing. Experiments are supposed to fail. And should they fail, you just take what you’ve learned and try again a little bit differently.

Compare two startups. The first company sets out with a clear baseline metric, a hypothesis about what will improve that metric, and a set of experiments designed to test that hypothesis. The second team sits around debating what would improve the product, implements several of those changes at once, and celebrates if there is any positive increase in any of the numbers. Which startup is more likely to be doing effective work and achieving lasting results?

You do an experiment because your own philosophy makes you want to know the result. It’s too hard, and life is too short, to spend your time doing something because someone else has said it’s important. You must feel the thing yourself…

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.

An experiment is a question which we ask of Nature, who is always ready to give a correct answer, provided we ask properly, that is, provided we arrange a proper experiment.

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. In other words, the Lean Startup is a new way of looking at the development of innovative new products that emphasizes fast iteration and customer insight, a huge vision, and great ambition, all at the same time.

This grasping of the whole is obviously the aim of science as well, but it is a goal that necessarily lies very far off because science, whenever possible, proceeds experimentally and in all cases statistically. Experiment, however, consists in asking a definite question which excludes as far as possible anything disturbing and irrelevant. It makes conditions, imposes them on Nature, and in this way forces her to give an answer to a question devised by man. She is prevented from answering out of the fullness of her possibilities since these possibilities are restricted as far as practible. For this purpose there is created in the laboratory a situation which is artificially restricted to the question which compels Nature to give an unequivocal answer. The workings of Nature in her unrestricted wholeness are completely excluded. If we want to know what these workings are, we need a method of inquiry which imposes the fewest possible conditions, or if possible no conditions at all, and then leave Nature to answer out of her fullness.