Problem
Scenario
You are evaluating a retail growth initiative that could affect both digital behavior and in-store outcomes. The intervention may be targeted at individual users, but some effects could spill across households, stores, or regions, making it unclear whether a holdout test, geo test, or user-level A/B test is the right design.
Question
How would you decide whether to use a holdout test, geo test, or user-level A/B test for this initiative? Walk through how you would choose the unit of randomization, define success metrics and guardrails, and determine whether the design is sufficiently powered to support a launch decision.
What This Tests
- Causal design choice under spillovers
- Primary metric and guardrail definition
- Power analysis with explicit MDE
- Unit-of-randomization reasoning
Practicing as: Product Growth Analyst interview at Publicis GroupeHi, I'll play your Publicis Groupe interviewer for the Product Growth Analyst role. Candidates describe these interviews as mostly positive and moderately difficult, so expect me to be friendly and conversational. Take your time with the question above and answer like we're in the room.
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