先定義事件，再畫漏斗

A useful measurement plan begins with language. If two people use the same event name to mean different things, the report will carry that disagreement into every discussion.

Write a human description

Describe the action each event represents and when it should happen. Include the difference between seeing a control and activating it. Identify the properties that provide useful context, while keeping personal information out of event names and unnecessary parameters.

Check representative journeys

Walk through a normal journey and a few variations. Consider repeated clicks, validation errors and returning to an earlier page. The question is whether the event sequence tells a faithful story of those actions, rather than simply whether something appears in a report.

Keep definitions with the work

Document changes to the measurement plan alongside changes to the interface. If the meaning of an event changes, record when and why. A clearly defined funnel supports better questions because the team can separate a change in customer behaviour from a change in how the journey is recorded.