If it disagrees with experiment, it’s wrong.
—Dr. Richard Feynman
Traditionally, UX design projects are framed by requirements and deliverables; teams are given requirements and expected to produce deliverables. Lean UX radically shifts the way we frame our work. Our goal is not to create a deliverable, it’s to change something in the world—to create an outcome. We start with assumptions instead of requirements. We create and test hypotheses. We measure to see whether we’ve achieved our desired outcomes.
This chapter covers the main tool of outcome-focused work: the hypothesis statement. The hypothesis statement is the starting point for a project. It states a clear vision for the work and shifts the conversation between team members and their managers from outputs (e.g., “we will create a single sign-on feature”) to outcomes (e.g., “we want to increase the number of new sign-ups to our service”).
The hypothesis statement is a way of expressing assumptions in testable form. It is composed of the following elements:
A high-level declaration of what we believe to be true.
More granular descriptions of our assumptions that target specific areas of our product or workflow for experimentation.
The signal we seek from the market to help us validate or invalidate our hypotheses. These are often quantitative but can also be qualitative.
Models of the people for whom we believe we are solving a problem.
The product ...