Your question is Measure Long-Term Retention Lift. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
You work on a product that has launched a new feature and early usage looks promising. The team wants to know whether the feature is actually improving long-term retention or only creating a short-lived spike in activity.
How would you measure whether the feature is driving durable retention rather than temporary engagement, and how would you structure the experiment so you can trust the result?