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DoorDash·Data Scientist·Technical Phone Screen·Senior

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Jul 2026Remote

Summary

DoorDash data science interview focused entirely on marketplace experimentation across three fairly meaty scenarios: auto-applying credits at checkout, duplicate restaurant listings in search, and a restaurant promotions product. No coding, just product analytics and experiment design the whole way through.

Questions Asked (8)

Q1

How would you design an experiment to test auto-applying customer credits at checkout by default, and what should the primary metric be?

A/B Testing & ExperimentationProduct Analytics & MetricsTechnical Trade-offs
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 goal: increase credit redemption and order completion. Then outline a randomized controlled experiment (A/B test) where the treatment auto-applies credits at checkout, and define the primary metric as the credit redemption rate, with guardrails like order completion and customer satisfaction.

Pro tip: Emphasize the importance of considering the long-term impact on customer behavior and the potential for cannibalization of future orders. Also, mention the need for a holdout group to measure incremental lift.

1. Define Hypothesis and Goal

State the hypothesis: auto-applying credits will increase credit redemption and order frequency. Clarify the primary goal: increase redemption rate without harming conversion or satisfaction.

2. Design Experiment

Randomly assign users to control (manual credit application) and treatment (auto-apply). Ensure proper randomization, sample size, and duration. Consider stratification by user segments.

3. Select Metrics

Primary metric: credit redemption rate. Secondary metrics: order completion rate, average order value, time to checkout. Guardrail metrics: customer satisfaction, refund rates, future order frequency.

4. Analyze and Interpret

Use statistical tests to compare groups. Check for novelty effects and segment-level impacts. Evaluate trade-offs between increased redemption and potential negative effects.

5. Decide and Iterate

Based on results, decide whether to roll out, iterate, or abandon. Consider long-term holdout to measure sustained impact.

Key Points to Mention

  • Randomization and control group setup
  • Primary metric: credit redemption rate
  • Guardrail metrics: order completion, customer satisfaction
  • Potential cannibalization and long-term effects
  • Sample size and power analysis
  • Segmentation by user behavior (e.g., frequent vs. infrequent users)

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

Q2

What tradeoffs exist between checkout conversion, credit burn, platform margin, and long-term retention when auto-applying credits?

Product Analytics & MetricsPricing & MonetizationProduct Sense & Ideation
Author's notes

Spent maybe too long on the short-term margin angle and didn't get deep enough into retention.

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AI HintsAI Generated

Suggested Approach

Start by defining each metric and the mechanism of auto-applying credits, then systematically analyze the tradeoffs between them using a framework that considers short-term vs. long-term effects and customer segments. Conclude with a recommendation on how to balance these tradeoffs, possibly through experimentation and targeting.

Pro tip: Frame the tradeoffs in terms of customer lifetime value (CLV) and incremental impact, emphasizing that the goal is to maximize long-term profitability, not just short-term conversion. Mention the importance of testing with holdout groups to measure true incrementality.

1. Define metrics and mechanism

Clearly define checkout conversion, credit burn, platform margin, and long-term retention. Explain how auto-applying credits works: credits are automatically applied at checkout, reducing the customer's out-of-pocket cost.

2. Analyze short-term tradeoffs

Discuss how auto-applying credits can increase checkout conversion by lowering friction and perceived cost, but also leads to higher credit burn (cost to platform) and lower platform margin per order.

3. Analyze long-term tradeoffs

Consider how auto-applying credits might affect long-term retention: it could increase retention by encouraging repeat purchases, but may also train customers to expect discounts, reducing willingness to pay full price later.

4. Segment and contextualize

Break down the impact by customer segments (e.g., new vs. existing, high-value vs. low-value) and order contexts (e.g., small vs. large orders). The tradeoffs may vary significantly across these groups.

5. Recommend and test

Propose a balanced approach, such as targeted auto-apply for specific segments or order values, and suggest A/B testing to measure the incremental impact on each metric.

Key Points to Mention

  • Incremental impact: Measure the true lift in conversion and retention due to auto-apply, not just correlation.
  • Customer lifetime value (CLV): Consider how changes affect long-term value, not just short-term metrics.
  • Credit burn and margin: Auto-apply increases credit redemption, which is a cost to the platform and reduces margin.
  • Retention and habit formation: Auto-apply may create dependency on discounts, impacting future willingness to pay.
  • Segmentation: Different customer segments (new, existing, high-value) may respond differently to auto-apply.
  • Experimentation: Use A/B tests with holdout groups to quantify tradeoffs and optimize the strategy.

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

Q3

When the top organic result and the top sponsored result in search are the same restaurant, is showing both listings good or bad for the marketplace?

Product Sense & IdeationProduct Analytics & MetricsPricing & Monetization
Author's notes

My gut said bad for users, good for the restaurant, neutral-to-bad for the platform.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the marketplace context (DoorDash's search ecosystem) and defining what 'good' means for each stakeholder: consumers, restaurants, and DoorDash. Then evaluate the impact on key metrics like conversion, user experience, and advertiser ROI, considering both short-term and long-term effects.

Pro tip: Acknowledge the tension between ad revenue and user trust, and propose a testable hypothesis (e.g., A/B test) to measure the true impact rather than relying on assumptions.

1. Clarify the scenario and stakeholders

Confirm that the question refers to DoorDash's search results where a restaurant appears both as an organic and sponsored listing. Identify the key stakeholders: consumers, restaurants, and DoorDash as the platform.

2. Define success metrics

Determine what metrics indicate a 'good' or 'bad' outcome for each stakeholder. For consumers: conversion rate, order completion, satisfaction. For restaurants: incremental orders, ROI on ads. For DoorDash: revenue, retention, marketplace health.

3. Analyze potential benefits and drawbacks

List pros (e.g., increased visibility for the restaurant, higher ad revenue for DoorDash) and cons (e.g., user annoyance, reduced trust, cannibalization of organic clicks). Consider both short-term and long-term effects.

4. Consider marketplace dynamics and trade-offs

Evaluate how showing both listings affects competition, ad auction efficiency, and overall marketplace fairness. Discuss whether it leads to a better or worse experience for users and restaurants.

5. Propose a data-driven approach

Suggest running an A/B test to measure the impact on key metrics. Outline how to interpret results and make a recommendation based on the trade-offs.

Key Points to Mention

  • User experience: potential confusion or annoyance from duplicate listings, leading to decreased trust.
  • Ad effectiveness: cannibalization of organic clicks, reducing the value of sponsored ads.
  • Restaurant perspective: increased visibility but potentially higher ad spend for the same orders.
  • DoorDash revenue: short-term ad revenue gain vs. long-term user retention and marketplace health.
  • Marketplace fairness: impact on smaller restaurants that cannot afford ads.
  • Testing methodology: A/B test to measure incremental impact on conversion, order value, and user satisfaction.

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

Q4

If you decide to remove duplicate restaurant listings from search results, how would you test that change and what metrics would cover user experience, ad performance, and overall marketplace value?

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

Felt more comfortable here.

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AI HintsAI Generated

Suggested Approach

Start by framing the change as a hypothesis about improving user experience and marketplace efficiency, then outline a rigorous A/B test design with guardrail metrics. Structure your answer around three metric pillars: user experience (e.g., search success, time to conversion), ad performance (e.g., ad CTR, revenue per search), and marketplace value (e.g., overall orders, restaurant diversity).

Pro tip: Emphasize that removing duplicates could reduce ad impressions and short-term revenue, so you must balance short-term ad metrics with long-term user retention and marketplace health. Propose a holdback or long-term holdout to measure cumulative effects.

1. Define Hypothesis and Success Criteria

Articulate the problem: duplicate listings may confuse users and reduce trust. State the hypothesis that deduplication will improve search relevance and user experience without harming ad revenue or marketplace health. Define primary success metrics (e.g., search-to-order conversion) and guardrails (e.g., ad revenue).

2. Design the Experiment

Propose an A/B test with random assignment at the user or session level. Ensure sufficient power by calculating sample size based on expected effect size. Consider stratification by user segment (new vs. existing) and restaurant category to detect heterogeneous effects.

3. Select Metrics Across Three Pillars

For user experience: search success rate, time to first click, conversion rate, and user satisfaction (e.g., NPS). For ad performance: ad CTR, ad impressions per search, ad revenue per search, and advertiser ROI. For marketplace value: total orders, gross order value (GOV), restaurant diversity (number of unique restaurants ordered from), and long-term retention.

4. Analyze and Interpret Results

Use statistical tests (e.g., t-test, bootstrap) to compare metrics between control and treatment. Check for novelty effects and segment-level differences. Evaluate trade-offs: if ad revenue drops but user experience improves, assess whether long-term gains outweigh short-term losses.

5. Recommend and Monitor

Based on results, recommend rollout, iteration, or rejection. If rolled out, set up ongoing monitoring with dashboards and alerts for key metrics. Consider a long-term holdout to measure sustained impact on marketplace value.

Key Points to Mention

  • A/B test design with proper randomization and power analysis
  • User experience metrics: search success rate, time to conversion, user satisfaction
  • Ad performance metrics: ad CTR, ad revenue per search, advertiser ROI
  • Marketplace value metrics: total orders, GOV, restaurant diversity, long-term retention
  • Guardrail metrics to detect negative impacts on ad revenue or restaurant partners
  • Segment analysis to identify heterogeneous effects (e.g., new vs. existing users, cuisine types)

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

Q5

How would removing a duplicate listing affect lower-ranked restaurants, and how do you account for that in your experiment design?

A/B Testing & ExperimentationTechnical Trade-offsProduct Analytics & Metrics
Author's notes

Short answer: it's a spillover problem.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the marketplace dynamics: removing a duplicate listing reduces supply for that restaurant, which can shift consumer demand to lower-ranked alternatives. Then outline how your experiment design isolates this effect by randomizing at the market level and measuring both substitution and cannibalization metrics.

Pro tip: Frame the answer around the two-sided marketplace: removing a duplicate helps the restaurant (less confusion, better conversion) but may hurt lower-ranked restaurants if demand doesn't shift to them. Show you understand the trade-off between supply quality and fairness in ranking.

1. Clarify the mechanism

Explain how duplicate listings affect search and ranking: duplicates can split demand, inflate visibility, or create confusion. Removing them changes the competitive set for lower-ranked restaurants.

2. Define the counterfactual and treatment

Specify what 'removing a duplicate' means operationally (e.g., merging listings, deduplication) and what the control group sees. Ensure the treatment is applied consistently across markets.

3. Choose randomization unit and metrics

Randomize at the market or city level to avoid interference, since consumers can switch between restaurants. Use metrics like order volume, conversion rate, and market share for lower-ranked restaurants.

4. Account for spillover and substitution

Measure whether demand shifts to lower-ranked restaurants or exits the platform. Use difference-in-differences or synthetic control to estimate the causal effect on lower-ranked restaurants.

5. Validate and iterate

Check for novelty effects, run power analysis, and consider heterogeneous treatment effects by cuisine, price, and geography. Be ready to adjust the design if spillover is detected.

Key Points to Mention

  • Marketplace interference and the need for cluster randomization
  • Substitution effects: demand may shift to lower-ranked restaurants or to competitors
  • Metrics: order volume, conversion rate, market share, and restaurant-level cannibalization
  • Difference-in-differences or synthetic control to isolate the effect
  • Heterogeneous treatment effects by restaurant rank, cuisine, and geography
  • Long-term vs. short-term effects and novelty bias

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

Q6

How would you increase restaurant adoption of the existing fixed-discount promotion feature?

Product Sense & IdeationProduct StrategyProduct Analytics & Metrics
Author's notes

Went broad here maybe too fast.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the goal (e.g., increase adoption rate or total promotions) and the current adoption baseline. Then structure your answer around a data-driven funnel: identify barriers to adoption, propose targeted solutions (e.g., better targeting, incentives, UX improvements), and define success metrics and an experimentation plan.

Pro tip: Emphasize that adoption should be driven by value for both restaurants and DoorDash—focus on ROI for restaurants and incremental profit for DoorDash, not just pushing the feature. Mention that you would run a pilot with a small set of restaurants to validate hypotheses before scaling.

1. Clarify Goal & Baseline

Ask clarifying questions to understand what 'increase adoption' means (e.g., % of restaurants using the feature, frequency of use) and the current adoption rate. Identify the target segment and any constraints.

2. Diagnose Barriers

Analyze data to identify why restaurants aren't adopting: lack of awareness, perceived low ROI, operational complexity, or misalignment with their strategy. Segment restaurants by size, cuisine, and past promotion behavior.

3. Ideate Solutions

Brainstorm interventions across the funnel: awareness (education, case studies), consideration (ROI calculator, personalized recommendations), and adoption (incentives, simplified setup, integration with POS). Prioritize based on impact and effort.

4. Define Metrics & Experiment

Define success metrics (adoption rate, incremental orders, restaurant retention, ROI). Design A/B tests or pilots to measure the impact of each intervention, ensuring statistical power and guardrail metrics.

5. Scale & Iterate

Based on experiment results, roll out successful interventions to broader segments. Continuously monitor and iterate, using feedback loops to refine the approach.

Key Points to Mention

  • Segment restaurants by characteristics (e.g., size, cuisine, current promotion usage) to tailor interventions.
  • Quantify the value proposition for restaurants: show how the feature increases orders, revenue, or customer acquisition.
  • Leverage data to personalize outreach and recommendations (e.g., 'restaurants like yours saw X% increase').
  • Simplify the user experience for setting up and managing promotions to reduce friction.
  • Consider incentives such as reduced commission on promotional orders or temporary boosts in search ranking.
  • Define clear success metrics and run controlled experiments to measure incremental impact.

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

Q7

If restaurants can customize their promotion format rather than using a fixed template, how would you design and test that product?

A/B Testing & ExperimentationPricing & MonetizationTechnical Trade-offs
Author's notes

This is where the two-sided marketplace complexity really hit.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the business goal and constraints, then propose a flexible promotion builder with guardrails. Outline a phased testing plan that starts with qualitative research and small-scale experiments, then scales to a full A/B test measuring impact on key metrics like orders, revenue, and merchant satisfaction.

Pro tip: Emphasize the importance of defining success metrics upfront and considering network effects and interference between restaurants, which can bias A/B tests in marketplaces.

1. Clarify Objectives and Constraints

Ask clarifying questions to understand the business goal (e.g., increase orders, merchant retention) and technical constraints (e.g., existing systems, data availability).

2. Design the Product

Propose a customizable promotion format with modular components (e.g., discount type, threshold, duration) and guardrails to prevent abuse or margin erosion.

3. Define Metrics and Hypotheses

Identify primary and secondary metrics (e.g., order volume, average order value, merchant retention) and formulate clear hypotheses for testing.

4. Plan the Experiment

Outline a phased approach: start with qualitative user research, then run a pilot with a small set of restaurants, followed by a randomized controlled trial (A/B test) with proper randomization and power analysis.

5. Analyze and Iterate

Analyze results for statistical significance and practical impact, check for heterogeneous treatment effects, and decide whether to launch, iterate, or abandon.

Key Points to Mention

  • Randomization unit: restaurant-level vs. consumer-level to avoid contamination
  • Network effects and interference in marketplace experiments
  • Guardrails to prevent promotion abuse and ensure profitability
  • Use of holdout groups and long-term metric tracking
  • Segmentation analysis to understand which restaurants benefit most
  • Technical implementation: feature flags, scalable data pipeline

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

Q8

How would you compare the new customizable promotion product against the old fixed-template product, and how do you separate incremental lift from cannibalization or adverse selection?

A/B Testing & ExperimentationProduct Analytics & MetricsRoot Cause Analysis
Author's notes

Probably the hardest question in the whole interview.

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AI HintsAI Generated

Suggested Approach

Start by defining clear success metrics for the promotion product, such as incremental orders, profit, and customer retention. Then propose a randomized controlled experiment (A/B test) with a holdout group to measure the true incremental impact, and use techniques like difference-in-differences or causal inference to separate incremental lift from cannibalization and adverse selection.

Pro tip: Emphasize the importance of a long-term holdout to measure the sustained impact and avoid novelty effects. Also, consider heterogeneous treatment effects to identify which customer segments benefit most and where cannibalization is likely.

1. Define Success Metrics

Identify key metrics such as incremental orders, gross profit, customer acquisition, and retention. Distinguish between primary and secondary metrics.

2. Design Experiment

Propose a randomized controlled trial with a holdout group that receives no promotion. Ensure proper randomization and sufficient power to detect meaningful effects.

3. Measure Incremental Lift

Compare the treatment group (new customizable promotion) against the control group (old fixed-template or no promotion) to estimate the incremental impact on the key metrics.

4. Separate Cannibalization and Adverse Selection

Use techniques like difference-in-differences, propensity score matching, or instrumental variables to isolate the incremental effect from cannibalization (e.g., orders that would have happened anyway) and adverse selection (e.g., customers who only purchase with promotions).

5. Analyze Heterogeneous Effects and Long-term Impact

Segment customers to understand varying effects and run a long-term holdout to assess sustained impact and potential novelty effects.

Key Points to Mention

  • Randomized controlled experiment with holdout group
  • Incremental lift calculation (treatment vs. control)
  • Cannibalization: orders that would have occurred without promotion
  • Adverse selection: customers who are promotion-sensitive and less profitable
  • Difference-in-differences or causal inference methods
  • Long-term holdout to measure sustained impact and novelty effects

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