Determine Demand for WhatsApp Group Video-Calls
Company: Meta
Role: Data Scientist
Category: Analytics & Experimentation
Difficulty: hard
Interview Round: Technical Screen
##### Scenario
WhatsApp is considering launching a group video-call feature; currently it does not exist.
##### Question
a) Using the available call-level data, outline how you would determine whether there is demand for group calls.
b) What additional quantitative and qualitative data would you request, and how would you analyze it?
c) After launch, list success and guard-rail metrics; if you could keep only one success metric, which one and why?
d) Before launch, engineering asks for an experiment design—describe step-by-step how you would run and analyze the test, including randomization unit, clustering to reduce spill-over, novelty effects, and criteria for statistical & business significance.
##### Hints
Frame analysis: opportunity sizing → metric hierarchy → clustered A/B test design → interpretation of lift vs. risk.
Quick Answer: This question evaluates proficiency in opportunity sizing, metric hierarchy development, and experimental design for new product features, including clustered A/B testing and interpretation of lift versus risk.