Design and validate an ads feed experiment
Company: Meta
Role: Data Scientist
Category: Analytics & Experimentation
Difficulty: hard
Interview Round: Onsite
Quick Answer: This question evaluates a data scientist's competency in experiment design, causal inference, and applied statistical analysis for product experimentation, covering KPI definition, sample-size and power calculations, multiple-comparison adjustments, pre/post-launch validation, variance-reduction techniques, ramping and randomization choices, interference detection, and sequential monitoring; it falls under the Analytics & Experimentation domain and tests both conceptual understanding and practical application. It is commonly asked because interviewers need evidence that a candidate can align experimentation with business goals (maximizing long-term ad revenue while protecting engagement), translate operational constraints into duration and traffic estimates, and reason about statistical trade-offs and operational safeguards such as ramp plans and cross-experiment contamination controls.