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Meta·Data Scientist·Technical Phone Screen·Senior

Senior
Apr 2026

Summary

Meta DS interview centered on a single meaty product analytics case about launching a group video call feature. The question had a lot of moving parts and I felt like I was juggling too many threads at once.

Questions Asked (1)

Q1

You have access to messaging data, friend graphs, and survey results. How would you measure latent demand for a group video calling feature, define success metrics for its launch, design an experiment to evaluate it, and use data to decide on an initial cap for the number of participants per call?

Product Analytics & MetricsA/B Testing & ExperimentationProduct Sense & Ideation
Author's notes

This is four questions stapled together and I did not handle the transition between parts gracefully.

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AI HintsAI Generated

Suggested Approach

Start by triangulating latent demand from messaging data (e.g., frequency of group chats, attempts to start group calls), friend graph (e.g., cluster density, overlapping social circles), and survey results (e.g., stated interest, pain points). Then define success metrics that capture adoption, engagement, and retention, design an A/B test with a holdout to measure causal impact, and use experimental data to determine the optimal participant cap by analyzing engagement and quality metrics across different group sizes.

Pro tip: Focus on behavioral data over stated preferences: survey interest often overstates actual usage. Also, when determining the cap, consider network effects and diminishing returns—the optimal size may be where marginal engagement gains flatten or drop due to coordination costs.

1. Triangulate latent demand

Analyze messaging data for group chat frequency, call initiation attempts, and drop-off points; use friend graph to identify dense clusters and cross-group connections; and incorporate survey results to understand unmet needs and willingness to use.

2. Define success metrics

Select a North Star metric (e.g., weekly active group calls per user) and supporting metrics for adoption (e.g., % of eligible users trying feature), engagement (e.g., average call duration, frequency), and quality (e.g., call success rate, user satisfaction).

3. Design experiment

Run an A/B test with a control group (no feature) and treatment groups (feature enabled with varying participant caps). Randomize at user or group level, ensure sufficient power, and measure causal impact on key metrics.

4. Analyze and decide on cap

Use experiment data to plot engagement and quality metrics against group size. Identify the point where marginal gains diminish or negative effects (e.g., technical issues, social loafing) emerge, and set the cap accordingly.

Key Points to Mention

  • Use behavioral proxies (e.g., group chat size, call attempts) to infer latent demand beyond surveys.
  • Leverage friend graph to identify natural group sizes and social clusters for targeting.
  • Define metrics across the funnel: awareness, adoption, engagement, retention, and quality.
  • Design experiment with multiple treatment arms to test different caps (e.g., 4, 8, 16 participants).
  • Consider network effects and interference when randomizing; use cluster randomization if needed.
  • Balance technical constraints (bandwidth, latency) with user experience when setting the cap.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.