This question evaluates a data scientist's competency in metric definition, causal inference, experimental design, and observational analysis within the Analytics & Experimentation domain for a Data Scientist role.

You have impression- and engagement-level logs for a social feed. Posts are created by authors and viewed by audiences who may be either:
The product team wants to know if posts from friends lead to more social interactions, and what additional value unconnected audiences provide.
Outline how you would validate, using available data, that content from friends is more social than content from unconnected viewers. Include:
Login required