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Design a Real-Time Personalized Ad Selection System

UpstartData Scientist · Technical Screen
HardData ScientistTechnical ScreenMachine Learning

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This interview question evaluates core ML concepts, assumptions, math intuition, training/evaluation trade-offs, and practical failure modes in a realistic interview setting. A strong answer for Design a Real-Time Personalized Ad Selection System states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

Scenario

You are asked to build a data-driven advertising platform that serves personalized ads to millions of users in real time.

Question

Design an end-to-end machine-learning system for ad selection: discuss data collection, labeling, feature engineering, model choice, exploration-exploitation strategy, online/offline evaluation, latency constraints, and scalability.

Hints

CTR prediction with logistic regression/GBDT, counterfactual evaluation, feature store, bandits for exploration.