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Meta·Data Scientist·Technical Phone Screen·Senior

Senior
Jul 2026

Summary

Meta DS interview with a product analytics focus, this one centered on push notifications for a travel app. The question had a few layers and I don't think I fully nailed the interference piece.

Questions Asked (2)

Q1

For a new push notification feature in a travel recommendation app, what primary success metrics would you track, and which guardrail metrics would you include to catch negative effects like uninstalls or unsubscribes?

Product Analytics & MetricsA/B Testing & Experimentation
Author's notes

I went straight to engagement stuff: click-through rate, sessions driven by the notification, maybe bookings if the app had that.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the feature's goal—driving engagement with travel recommendations—and define primary success metrics that directly measure that goal, such as click-through rate and bookings. Then, identify guardrail metrics that capture potential negative side effects, like uninstalls, unsubscribes, and notification disablement, ensuring a balanced evaluation of the feature's impact.

Pro tip: Emphasize that guardrail metrics should be monitored with non-inferiority tests to ensure the feature doesn't harm key health metrics, and consider segmenting by user engagement levels to detect heterogeneous effects.

1. Clarify the feature's objective

Understand that the push notification feature aims to increase user engagement with travel recommendations, ultimately driving bookings or other core actions.

2. Define primary success metrics

Select metrics that directly measure the feature's success in achieving its objective, such as notification click-through rate, conversion rate to booking, and frequency of app opens attributed to notifications.

3. Identify guardrail metrics

Choose metrics that capture potential negative consequences, including uninstall rate, notification unsubscribe/disable rate, and user-reported satisfaction or spam reports.

4. Consider secondary and counter metrics

Include additional metrics like overall app engagement, retention, and long-term user value to ensure the feature doesn't cannibalize other interactions.

5. Plan for experimentation and analysis

Design an A/B test to measure these metrics, with proper sample size and duration, and plan to analyze results with statistical rigor, checking for novelty effects and segment-level impacts.

Key Points to Mention

  • Primary metrics should be aligned with the feature's goal, e.g., click-through rate (CTR) and conversion rate.
  • Guardrail metrics must include uninstall rate and unsubscribe/disable rate to monitor negative user reactions.
  • Consider notification frequency and relevance to avoid user annoyance.
  • Use A/B testing to isolate the feature's impact and measure metrics accurately.
  • Segment analysis by user activity level or travel intent to detect differential effects.
  • Long-term metrics like retention and lifetime value should be monitored to ensure sustained benefit.

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

Q2

The app has strong network effects because users share itineraries with each other. How would you design an A/B test for the push notification feature to reduce interference between groups, and what would your unit of randomization be?

A/B Testing & ExperimentationProduct Analytics & Metrics
Author's notes

This is where I kind of stumbled.

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AI HintsAI Generated

Suggested Approach

Start by acknowledging the challenge of network effects in A/B testing, then propose a cluster-based randomization approach to minimize interference. Explain how you would define clusters based on sharing behavior, choose appropriate metrics, and analyze results with methods that account for clustering.

Pro tip: Consider using a switchback or time-based randomization if clusters are hard to define, but be prepared to discuss trade-offs. Also, mention that you would run a power analysis to determine the number of clusters needed.

1. Identify interference sources

Analyze how push notifications might affect users beyond the individual, such as through shared itineraries or social connections. Determine the potential spillover effects that could bias the experiment.

2. Define randomization unit

Choose a unit that groups interacting users, such as a cluster of friends, a social network component, or a geographic region. Explain why this unit minimizes interference while maintaining statistical power.

3. Design the experiment

Outline the A/B test setup: how clusters are assigned to treatment/control, the duration, and the metrics (e.g., notification engagement, itinerary shares, retention). Mention any guardrail metrics to monitor.

4. Analyze results with clustering

Use statistical methods that account for cluster randomization, such as cluster-robust standard errors or mixed-effects models. Discuss how to interpret results and check for interference.

5. Validate and iterate

Suggest running a holdout or a follow-up experiment to confirm findings. Consider if the cluster design introduces biases and how to mitigate them.

Key Points to Mention

  • Network effects and interference in A/B testing
  • Cluster randomization as a solution
  • Defining clusters based on social graph or sharing behavior
  • Metrics: engagement, shares, retention, and guardrails
  • Statistical power and sample size considerations
  • Potential biases and how to address them

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