How do I approach Statistics & Math interview questions?

Statistics & Math questions require understanding of core concepts and practice. PracHub provides solutions with explanations to help you master statistics & math interviews.

What difficulty level is this interview question?

This is a hard difficulty Statistics & Math question, commonly asked during Onsite rounds at Meta.

What role is this question designed for?

This question is commonly asked for Data Scientist candidates at Meta during technical interviews.

Choose Randomization Unit and Mitigate Network Effects

Last updated: Mar 29, 2026

Quick Overview

This question evaluates a candidate's competency in experimental design and causal inference, specifically selecting appropriate randomization units, detecting and mitigating network interference, and estimating direct versus spillover effects.

A/B Test Design for a New Messenger Feature with Network Effects

Context

You are designing an A/B test for a new Messenger feature in a social messaging app. Users communicate via one-to-one and group conversations. Because people interact, there is a risk that a participant's assignment could influence their peers' outcomes (network interference), violating the standard "no interference" assumption of A/B tests.

Tasks

Choose an appropriate randomization unit (e.g., user-level, conversation/thread-level, cluster/graph-level) and justify your choice given potential network effects.
Describe practical diagnostics and statistical tests you would use to detect network effects if they occur.
Propose design and analysis methods to mitigate bias from network effects and to estimate both direct and spillover effects. Where useful, mention methods such as CUPED and difference-in-differences.

Solution

Show

Comments (0)

Loading comments...

Browse More Questions

More Statistics & Math•More Meta•More Data Scientist•Meta Data Scientist•Meta Statistics & Math•Data Scientist Statistics & Math