Airbnb·Data Scientist·Technical Phone Screen
Jul 2026
Airbnb data scientist interview that was basically a full take-home disguised as a technical screen. One massive pandas question covering sessionization, funnel analysis, segment metrics, and statistical lift calculations. A lot to fit into one sitting.
- Given a raw events table and a guests table, write idiomatic vectorized Pandas to: sessionize events per guest using a 30-minute inactivity timeout, filter bot traffic, then compute segment-level metrics (unique guests, sessions, session-level and guest-level conversion rates, average sessions-to-first-order, and median time from first page_view to first order_completed) broken out by traffic_source and device. Restrict the analysis to a 7-day window ending 2025-09-01.
- Using the same event data, build a de-duplicated guest funnel for page_view, add_to_cart, checkout_start, and order_completed over the 7-day window. Each guest should be counted once at their highest attained step. Report step-through rates and absolute drop-offs.
- After filtering segments with fewer than 100 sessions, identify the top 5 segments by lift versus the sitewide guest-level conversion rate. Report both the lift and the 95% Wilson confidence interval for each segment's conversion rate.
- How do you handle guests who complete an order_completed event in the window but have no earlier events in the same window? Implement a specific rule: pull their first event from the prior 24 hours if available, otherwise treat them as a direct single-step conversion.
- How would you adapt this Pandas pipeline to run at scale in PySpark? What are the key translation points?
“The sessionization part is where I spent most of my mental energy.” The rest of the author's notes on Data Scientist interview at Airbnb, Technical Phone Screen round, covers how they worked through the question, what the panel pushed back on, and what they would do differently.
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