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Meta·Data Scientist·Technical Phone Screen·Senior

Senior
Apr 2026

Summary

Meta DS interview with a meaty experiment design question around a new Instagram Shopping feature. One question but it had a lot of layers to it, felt like they were testing whether you'd actually worked through a real launch before.

Questions Asked (1)

Q1

Instagram is rolling out an in-app Shopping feature. How would you design an experiment to measure its impact on user engagement and revenue? What metrics and success criteria would you track, and how would you handle selection bias or network effects?

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

This is the kind of question where you think you're doing fine and then the follow-ups expose all the stuff you glossed over.

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AI HintsAI Generated

Suggested Approach

Start by defining clear hypotheses about how the Shopping feature affects user engagement and revenue, then design a randomized controlled experiment (A/B test) with appropriate metrics and guardrails. Address potential biases like selection bias and network effects by using techniques such as cluster randomization or switchback testing, and plan for robust analysis.

Pro tip: At Meta, it's crucial to consider both short-term and long-term effects, and to use holdout groups to measure incremental impact. Also, be mindful of cross-platform interactions and novelty effects.

1. Define Hypotheses and Goals

Clearly state the primary hypothesis (e.g., Shopping increases engagement and revenue) and secondary hypotheses. Define what success looks like for both engagement and revenue.

2. Choose Experimental Design

Decide on randomization unit (user-level, cluster-level) and address network effects. Consider using cluster randomization, switchback testing, or a holdout group to isolate the feature's impact.

3. Select Metrics and Success Criteria

Identify key metrics: engagement (time spent, likes, comments, shares), revenue (ad revenue, purchase conversion), and guardrail metrics (user retention, satisfaction). Define minimum detectable effect and statistical power.

4. Address Biases and Confounders

Mitigate selection bias through proper randomization and stratification. Handle network effects by using cluster randomization or measuring spillover. Consider novelty effects and seasonality.

5. Analyze and Interpret Results

Use appropriate statistical methods (e.g., t-tests, regression, CUPED) to analyze results. Check for heterogeneous treatment effects and long-term impact. Make a recommendation based on statistical and practical significance.

Key Points to Mention

  • Randomization unit and potential network effects (e.g., social influence, spillover)
  • Key metrics: engagement (DAU, time spent, interactions) and revenue (ARPU, conversion rate, ad revenue)
  • Guardrail metrics to ensure no negative impact on user experience
  • Statistical power and minimum detectable effect to determine sample size
  • Techniques to handle selection bias: stratification, matching, or propensity score weighting
  • Long-term holdout or switchback design to measure sustained impact

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