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DoorDash·Software Engineer·Technical Phone Screen·Intermediate

Intermediate
Jun 2026

Summary

DoorDash data science interview with a classic ops metrics question. Nothing too surprising in format but the question itself has some depth to it if you actually know the delivery funnel.

Questions Asked (1)

Q1

How would you investigate a week-over-week 10% drop in successful deliveries?

Root Cause AnalysisProduct Analytics & Metrics
Author's notes

My first instinct was to jump straight to dasher supply, which in hindsight was too narrow.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the metric definition and scope of the drop (e.g., time period, regions, platforms) to ensure you're solving the right problem. Then systematically segment the data to isolate the cause, considering both technical and business factors. Finally, validate hypotheses with data and propose actionable next steps.

Pro tip: Demonstrate a hypothesis-driven approach by prioritizing the most likely causes first (e.g., recent deployments, external events) and using a process of elimination. Also, emphasize the importance of quantifying the impact and communicating findings clearly to stakeholders.

1. Clarify and Define

Confirm the exact metric definition, time frame, and scope (e.g., all regions or specific ones). Ask clarifying questions to understand if the drop is sudden or gradual, and if it's consistent across platforms.

2. Segment and Visualize

Break down the metric by dimensions such as region, platform, delivery partner, restaurant, and time of day. Use dashboards or queries to identify which segments are most affected.

3. Check for Technical Issues

Investigate recent code deployments, infrastructure changes, or third-party service outages. Look at error logs, latency metrics, and success rates of dependent services.

4. Analyze Business and External Factors

Consider changes in user behavior, marketing campaigns, competitor actions, weather events, or holidays. Correlate with business metrics like order volume, cancellation rates, and customer support tickets.

5. Validate and Act

Form hypotheses and test them with data (e.g., A/B tests, cohort analysis). Once root cause is identified, propose fixes, monitor impact, and communicate findings.

Key Points to Mention

  • Metric definition: What constitutes a 'successful delivery'? (e.g., on-time, no cancellation, etc.)
  • Segmentation: By geography, platform (iOS/Android), delivery partner, restaurant, time
  • Technical factors: Recent deployments, bugs, API failures, infrastructure issues
  • Business factors: Marketing campaigns, pricing changes, competitor promotions
  • External factors: Weather, holidays, local events, traffic
  • Data validation: Ensure data pipeline integrity and no reporting errors

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