Your question is Designing a Personalization Experiment. 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're evaluating a new recommendation idea on a product surface where users may see either the current experience or a personalized one. You need a simple, credible way to measure whether the new treatment improves user behavior.
How would you design a simple experiment to test a new recommendation or personalization idea?