What is an experiment?

So far in this book, I have tried to avoid the words test or experiment, but ultimately, a large part of what we've explored so far has been about running tests and experimenting with new code. When we looked at rollouts in Chapter 4, Percentage and Ring Rollouts, I emphasized validating whether the features are technically working and that they are adding the expected value to customers. This can be termed as an experiment.

While I did not state the validation of a rollout in the terms of an experiment, there was effectively a hypothesis being validated by rolling out a feature to a percentage or ring of the customers. For example, when ensuring that something is technically working as expected, the hypothesis would be that the new code is going to work as expected and meet the technical requirements. When we enable that for 10% of the customers and gather telemetry to ensure that this is indeed the case, we are testing the hypothesis. By rolling that...