Your question is Measuring Success. 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).
How do you measure success?
Keep your answer focused on how you would define success for a product or initiative, not just a single vanity metric. Clarify the primary KPI, the supporting leading indicators, and any guardrails you would use to avoid optimizing the wrong outcome.