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DoorDash·Data Scientist·Technical Phone Screen·Intermediate

Intermediate
May 2026

Summary

DoorDash data science interview with a product analytics case built around cold food delivery complaints. The question was open-ended enough that it could go a lot of directions, which was both the fun and the frustrating part.

Questions Asked (1)

Q1

Customers are complaining that their food arrives cold. Walk through how you'd investigate the root cause, what data and metrics you'd look at, what experiments you'd run, and what changes you'd actually recommend.

Root Cause AnalysisA/B Testing & ExperimentationProduct Analytics & Metrics
Author's notes

This one sprawled in a way I wasn't fully ready for.

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AI HintsAI Generated

Suggested Approach

Start by framing the problem as a funnel: order → prep → pickup → delivery → handoff, and identify where temperature loss occurs. Then propose a data-driven investigation using existing metrics and logs, followed by targeted experiments to validate hypotheses. Finally, recommend changes prioritized by impact and feasibility, with clear success metrics.

Pro tip: Don't jump to solutions like insulated bags; first quantify the problem and segment by restaurant, dasher, distance, and time of day to find the biggest lever. Also, consider that 'cold' is subjective—define a measurable proxy like temperature at delivery or time-out-of-oven.

1. Define and Quantify the Problem

Clarify what 'cold' means (e.g., temperature below threshold, customer rating) and quantify its prevalence using complaint rates, ratings, and delivery timestamps. Segment by geography, restaurant type, order size, and time.

2. Map the Delivery Funnel and Identify Hypotheses

Break down the order-to-delivery process into stages: food prep, waiting for dasher, dasher travel, and handoff. Form hypotheses about where heat loss occurs, such as long prep-to-pickup times or multiple deliveries.

3. Analyze Data to Validate Hypotheses

Use existing data (order logs, GPS, timestamps) to correlate cold complaints with factors like total delivery time, dasher wait time, distance, and batching. Run statistical tests to identify significant drivers.

4. Design and Run Experiments

Prioritize hypotheses and run A/B tests, e.g., testing insulated bags, optimizing dispatch to reduce wait times, or adjusting batching algorithms. Measure impact on temperature proxy and customer satisfaction.

5. Recommend Changes and Monitor

Based on experiment results, recommend scalable changes (e.g., new packaging standards, dispatch tweaks) and define ongoing metrics to track improvement, ensuring changes are cost-effective.

Key Points to Mention

  • Use of existing metrics: delivery time, dasher wait time, batching rate, customer ratings, complaint rates.
  • Segmentation: by restaurant, cuisine, distance, time of day, weather, and dasher experience.
  • Temperature proxy: time from food ready to delivery, or use of IoT sensors in pilot.
  • A/B testing: randomize at order or dasher level, ensure sufficient power, measure both temperature and satisfaction.
  • Root cause analysis techniques: funnel analysis, regression, cohort analysis.
  • Trade-offs: cost of insulated bags vs. impact, potential increase in delivery time if using bags, operational complexity.

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