Senior interview questionAsked at Uber · interview write-up
How would you build ranking for a food-delivery marketplace, from training labels and objectives to features, architecture and evaluation?
Model answer
Two stages: retrieve a few hundred eligible stores, filtered by delivery radius and opening hours, then rank them.
Labels come from the funnel: click, add to cart, order, with orders the main target. A multi-task model predicts each step, and the final score blends them with business terms like delivery time and fees. Features: user history and cuisine affinity, store quality, ETA, price, time and location. Labels carry position bias, so log position and correct for it. Evaluate offline with NDCG against orders, then A/B test orders per session, gross bookings and retention.
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