Your question is Incremental Loyalty Benefit Analysis. 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 loyalty program where a new benefit has been introduced for a subset of members. Early results suggest the treated group is using the benefit, but stakeholders are unsure whether it is changing behavior or simply rewarding members who were already likely to engage.
How would you analyze whether the benefit is creating incremental behavior versus just capturing existing behavior? What would you define as the primary metric, guardrails, and experiment setup to make that call?