Form Abandonment
When a visitor starts filling in a form, typing into at least one field, but leaves before submitting it.
Form abandonment is distinct from never engaging with the form at all. The visitor began, which means the offer was interesting enough to start, and then something in the form itself stopped them: too many fields, an unclear question, a validation error, a request for a phone number, or a step that appeared after they thought they were done.
Measuring it requires field-level events, not just views and submissions. Record which field was last focused before the visitor left, and the pattern usually points at one culprit. In multi-step forms, step progression shows the same thing at a coarser level: a large drop between step two and step three tells you exactly where to look.
The fixes are mostly subtraction. Remove fields that do not change what you do with the lead, move optional questions to a later step or a follow-up email, show inline validation as the visitor types rather than after submit, and make the first step a single email field so the smallest possible commitment starts the process.
See it in practice