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Lyft·Data Scientist·Technical Phone Screen·Senior

Senior
May 2026

Summary

Lyft data science interview with a meaty product analytics case about coupon targeting. Single question but it went deep fast, covering segmentation, causal inference, and experiment design all in one thread.

Questions Asked (1)

Q1

A ride-sharing company wants to run a coupon campaign to grow commuter rides but has a limited budget. How would you figure out which users should actually get the coupon?

A/B Testing & ExperimentationProduct Analytics & MetricsProduct Strategy
Author's notes

The part I fumbled initially was jumping straight into segmentation without anchoring on what 'success' even means.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the campaign's objective and constraints, then propose a data-driven approach to identify users with the highest incremental impact per dollar. Focus on designing an experiment to measure heterogeneous treatment effects and targeting users who are most responsive to the coupon.

Pro tip: Emphasize that the goal is to maximize incremental rides, not just conversions—many users would ride without a coupon, so targeting should be based on uplift, not propensity. Mention that you'd validate the targeting strategy with a holdout group to measure true incrementality.

1. Clarify Objective and Constraints

Define the campaign's success metric (e.g., incremental commuter rides) and understand budget limitations, coupon value, and target audience.

2. Identify Potential Responders

Use historical data to segment users based on commute patterns, past coupon usage, and responsiveness. Consider features like ride frequency, time of day, and route regularity.

3. Estimate Incremental Impact

Apply causal inference methods (e.g., uplift modeling, A/B test with holdout) to predict which users would take more rides only if given a coupon.

4. Optimize Allocation Under Budget

Prioritize users with the highest predicted incremental rides per dollar spent. Use optimization techniques to allocate coupons within budget.

5. Validate and Iterate

Run a pilot experiment to measure actual lift and ROI, then refine the targeting model based on results.

Key Points to Mention

  • Incremental lift vs. baseline conversion: focus on users who would not ride without the coupon.
  • Uplift modeling or causal inference techniques to estimate individual treatment effects.
  • A/B testing with a control group to measure true incrementality and avoid selection bias.
  • Budget constraint optimization: maximize incremental rides per dollar, not just total rides.
  • Segmentation by commute patterns and user lifetime value to tailor coupon value.
  • Potential pitfalls: coupon cannibalization, selection bias, and long-term effects on user behavior.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.