Your question is Choose the Right Experiment Unit. 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 consumer or retailer experiment where the same shopper, household, or store may interact with the treatment more than once. The team is debating whether to analyze results at the impression, session, user, or store level, and there is concern that the wrong choice could bias the readout.
How would you choose the right unit of analysis for this experiment, and how would that choice change your metric definition, power analysis, and interpretation of the results?