Experiment Design: $1 Delivery-Fee Surcharge on Unprofitable Restaurants
Scenario
About 10% of fast-food restaurants on the platform are unprofitable. Product wants to add a $1 delivery-fee surcharge to orders from those restaurants to cover the deficit.
Task
Design an experiment to evaluate the impact of the $1 fee on:
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Restaurant-level profitability
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Order volume (conversion and frequency)
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Customer satisfaction
Include:
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Experimental unit and randomization plan (address marketplace spillovers/interference).
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Primary/secondary metrics and guardrails, with clear hypotheses.
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Sample size and duration guidance (state assumptions if needed).
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Analysis plan (e.g., ITT vs. TOT, variance reduction, decomposition of effects).
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Concrete techniques to increase statistical power (e.g., stratified randomization, CUPED, covariate blocking, geo-testing, longer horizon), and when to use each.
Assume the $1 fee is only applied to currently unprofitable restaurants. If needed, make minimal additional assumptions explicit.