A/B Test Design for a New Recommendation Algorithm
Context
You are evaluating a new recommendation algorithm in a consumer marketplace app (e.g., browsing menus and item recommendations). The goal is to measure its causal impact on revenue while safeguarding user experience and marketplace health.
Task
Design an online A/B test to measure the algorithm’s impact on revenue. Specifically:
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Define clear hypotheses and the primary outcome.
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Choose the unit of randomization and describe the assignment plan.
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Compute the required sample size (state assumptions, show formula, and a small numeric example).
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Define success metrics: primary metric, secondary metrics, and guardrails.
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After running the experiment, you obtain p = 0.08 for revenue lift:
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Interpret this result and recommend whether to ship.
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If randomization were not possible, explain how you would estimate causal impact and compare methods:
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Difference-in-differences
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Propensity score matching/weighting
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Instrumental variables
Hint: Demonstrate knowledge of hypothesis testing, power analysis, Type I/II errors, and causal inference techniques.