A/B Test Design: Checkout Cashback Program (PayPal)
Scenario
PayPal plans to launch a checkout cashback program (e.g., "Get 1–5% back when you pay with PayPal"). The goal is to evaluate whether offering cashback at checkout improves key business outcomes while remaining cost-effective and safe.
Task
Design, run, and analyze an A/B test to evaluate the cashback program.
Please cover
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Hypothesis and success criteria.
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Experiment design:
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Population and eligibility
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Unit of randomization and variants
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Exposure and assignment rules
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Sample size and test duration
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Metrics:
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Primary metric(s)
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Guardrail/safety metrics
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Secondary/diagnostic metrics
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Data needed and instrumentation.
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Analysis plan and statistical methods.
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Segmentation and heterogeneity of effects.
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Risks, biases, and mitigations (e.g., fraud, interference, novelty).
You may assume the feature is shown at checkout to eligible users and credits cashback after successful payment.