Should Uber double member discounts?
UberData Scientist · Technical ScreenLast updated
This problem tests your ability to design a controlled experiment for a two-sided marketplace and evaluate whether a discount-doubling strategy is statistically and economically viable.
The Problem
Uber is considering doubling the discount offered to loyalty program members for rides in a specific metropolitan market. As a Data Scientist, you are tasked with evaluating the impact of this change before a full rollout.
The Scenario
- Current state: Loyalty members get a 5% discount on rides.
- Proposed change: Increase discount to 10%.
- Primary objective: Determine if this change increases Net Revenue (Total Fare - Discounts) or if the volume increase (higher ride demand) is offset by the margin compression.
Your Task
- Experimental Design: Describe how you would set up an A/B test to measure the impact of this change. Specifically, address how you would handle the two-sided marketplace dynamics (riders and drivers) to avoid interference/spillover effects.
- Metric Definition: Define a 'North Star' metric and at least two 'Guardrail' metrics to monitor during the experiment.
- Power Analysis: Suppose you expect a 2% lift in ride volume. If your current standard deviation of daily ride volume is 10%, qualitatively explain the relationship between the sample size required, the significance level (alpha), and the desired power (1-beta).
- Decision Framework: If the test results show a statistically significant increase in ride volume but a neutral impact on Net Revenue, what further considerations would you weigh before recommending the roll-out?
Hints
Hint 1
Consider whether randomization should happen at the user level or the geographic cluster level to minimize network spillover.
Hint 2
Think about the impact of increased ride demand on driver wait times and surge pricing, and how that affects the 'neutral' revenue scenario.
Hint 3
Guardrail metrics should focus on operational health, such as driver availability or fulfillment rates, to ensure the discount doesn't break the marketplace balance.
Follow-up questions
- How would you account for 'cannibalization,' where members might have taken a ride anyway, effectively losing revenue on those bookings?
- If this experiment shows a positive impact, how would you test for heterogeneous treatment effects (e.g., does the discount work better for suburban commuters versus city-center users)?
- What statistical methods would you use to control for external shocks, such as a major local event or a competitor's price drop during the test period?
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