Zero-party data

Zero-party data is what customers tell you about themselves deliberately — a preference, a size, a due date, a reason for buying — usually through quizzes, onboarding questions or a preference centre. It answers things behaviour cannot infer, and it arrives with a clear expectation that you will use it. Only ask for what will visibly change what you send, because unused answers teach people to skip the form. Stated preferences also go stale faster than most teams refresh them.