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DoorDash·Data Scientist·Technical Phone Screen·Senior

SeniorPrefer not to say
May 2026Remote

Summary

DoorDash data science interview focused entirely on Dasher supply-side economics. Three meaty questions back to back covering program evaluation, experiment design, and compensation model tradeoffs. Felt more like a product analytics case study than a traditional DS interview.

Questions Asked (3)

Q1

How would you assess whether the Top-Dasher prioritization program should be launched?

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

This one tripped me up more than I expected.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the program's goal and success metrics, then outline a structured evaluation plan that combines business impact, user experience, and statistical rigor. Emphasize the need for an A/B test to measure causal effects, while also considering guardrail metrics and long-term holdout groups.

Pro tip: Frame your answer around the trade-off between short-term gains and long-term marketplace health, showing you understand DoorDash's three-sided marketplace. Mention that you'd align with cross-functional partners (Product, Engineering, Ops) early to define metrics and avoid siloed analysis.

1. Clarify Objectives and Hypotheses

Ask clarifying questions to understand what Top-Dasher prioritization aims to achieve (e.g., reduce delivery time, increase Dasher retention) and how success is defined. Formulate clear hypotheses about expected impacts on key stakeholders.

2. Define Metrics and Guardrails

Identify primary success metrics (e.g., delivery efficiency, Dasher satisfaction) and guardrail metrics (e.g., customer wait time, order cancellation rate) to ensure no unintended harm. Consider both short-term and long-term metrics.

3. Design Experiment and Power Analysis

Propose an A/B test with random assignment of Dashers or orders, ensuring sufficient sample size and power. Discuss potential interference between Dashers and how to mitigate it (e.g., cluster randomization).

4. Analyze Results and Validate

Plan to analyze results using appropriate statistical methods (e.g., t-tests, regression) and check for heterogeneous treatment effects. Validate findings with robustness checks and sensitivity analyses.

5. Make Recommendation and Consider Rollout

Synthesize findings into a clear recommendation, weighing statistical significance, practical significance, and business impact. If positive, propose a phased rollout with continued monitoring.

Key Points to Mention

  • A/B testing methodology and statistical significance
  • Guardrail metrics to monitor marketplace health
  • Long-term holdout groups to measure sustained impact
  • Heterogeneous treatment effects across Dasher segments
  • Business impact vs. user experience trade-offs
  • Cross-functional collaboration and stakeholder alignment

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

Q2

For an extra-pay incentive aimed at improving Dasher engagement: what primary success metrics would you track, and how would you design an A/B test for it including treatment, control, experiment length, sample size, and guardrail metrics?

A/B Testing & ExperimentationProduct Analytics & MetricsPricing & Monetization
Author's notes

Felt more comfortable here.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the incentive's goal—likely increasing Dasher engagement (e.g., hours worked, deliveries completed)—and select primary metrics that directly reflect that goal, such as average deliveries per active Dasher per week. Then design a rigorous A/B test with a clear treatment (extra pay), control (no extra pay), sufficient sample size and duration to detect meaningful effects, and guardrails like delivery quality and cost per delivery.

Pro tip: Emphasize that the incentive might attract Dashers who would have been active anyway (selection effect), so consider measuring incremental engagement via a holdout group and analyzing heterogeneous treatment effects by Dasher tenure or prior activity level.

1. Define Success Metrics

Identify primary metrics that directly measure engagement (e.g., deliveries per Dasher, active hours, retention) and secondary metrics like Dasher satisfaction. Ensure they are aligned with business goals and measurable.

2. Design Experiment Groups

Randomly assign Dashers to treatment (receive extra pay) and control (no extra pay). Ensure randomization is at the Dasher level and that groups are comparable via pre-experiment covariates.

3. Determine Sample Size and Duration

Calculate required sample size using power analysis (e.g., 80% power, 5% significance) based on expected effect size and variance. Choose experiment length to capture full behavior cycles (e.g., 4-6 weeks) while avoiding novelty effects.

4. Select Guardrail Metrics

Monitor metrics that should not degrade, such as delivery time, customer ratings, and cost per delivery. Set thresholds for stopping the experiment if guardrails are violated.

5. Analyze and Interpret Results

Compare primary metrics between groups using appropriate statistical tests. Check for heterogeneous effects and ensure results are robust (e.g., via bootstrapping). Consider long-term impact and scalability.

Key Points to Mention

  • Primary metric: incremental deliveries or active hours per Dasher, measured as difference between treatment and control.
  • Randomization unit: Dasher-level to avoid contamination, with stratification by key covariates like region or tenure.
  • Sample size calculation: based on minimum detectable effect (MDE), power (80%), significance level (5%), and expected variance.
  • Experiment duration: long enough to capture steady-state behavior (e.g., 4 weeks) and account for weekly seasonality.
  • Guardrail metrics: delivery quality (e.g., on-time rate, customer rating), cost per delivery, and Dasher safety incidents.
  • Potential pitfalls: novelty effect, selection bias, and interference between Dashers (e.g., if incentives change supply in a market).

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

Q3

What are the key tradeoffs between paying Dashers per order versus per unit of time, and how would you run an experiment to determine which model is better for marketplace health?

Technical Trade-offsA/B Testing & ExperimentationPricing & Monetization
Author's notes

Probably the most interesting question of the three.

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AI HintsAI Generated

Suggested Approach

Start by outlining the tradeoffs between per-order and per-hour pay from the perspectives of Dashers, customers, and the platform, focusing on incentives, cost, and marketplace efficiency. Then propose an A/B test with clear metrics for marketplace health, such as delivery times, acceptance rates, and retention, while addressing potential confounds and ethical considerations.

Pro tip: Emphasize that the best pay model may depend on market conditions (e.g., urban vs. rural) and that a one-size-fits-all approach is unlikely; suggest testing heterogeneous effects across markets.

1. Identify Key Tradeoffs

Discuss how per-order pay incentivizes speed and volume, potentially leading to rushed deliveries and lower quality, while per-hour pay incentivizes availability and may reduce urgency, affecting delivery times and costs.

2. Define Marketplace Health Metrics

Select metrics that capture marketplace health, such as delivery time, order completion rate, Dasher acceptance rate, customer satisfaction, Dasher retention, and cost per delivery.

3. Design the Experiment

Propose a randomized controlled trial (A/B test) where Dashers are randomly assigned to per-order or per-hour pay, ensuring proper randomization, sample size, and duration to detect meaningful effects.

4. Analyze and Interpret Results

Compare metrics between groups using statistical tests, check for heterogeneous effects across markets or Dasher segments, and consider qualitative feedback.

5. Address Limitations and Next Steps

Acknowledge potential confounds (e.g., Dasher selection bias, novelty effects), discuss ethical concerns, and suggest iterative testing or hybrid models if needed.

Key Points to Mention

  • Incentive alignment: per-order pay encourages speed and volume; per-hour pay encourages availability and quality.
  • Impact on Dasher earnings variability and retention.
  • Effect on customer experience: delivery time, accuracy, and satisfaction.
  • Platform costs and operational efficiency.
  • Experimental design: randomization, control, sample size, and duration.
  • Heterogeneity: differences across markets, times of day, and Dasher types.

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