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Meta·Data Scientist·Technical Phone Screen·Senior

Senior
May 2026

Summary

Meta data scientist interview focused on a product scenario around feed card design changes. Two meaty questions, both requiring you to think across metrics, revenue, and regional differences at the same time. Not a casual screen.

Questions Asked (2)

Q1

If the height of a post card is reduced by 15%, how would you measure the impact on user experience and engagement?

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

I went straight to visible posts per viewport and scroll velocity, which felt right, but I kind of glossed over ad impressions and how compressing cards changes the ad slot density.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the context: what is a 'post card'? Assume it's a UI element like a card in a feed. Then outline a structured experimentation plan: define success metrics (engagement, UX), design an A/B test, and analyze results. Emphasize the importance of guardrail metrics and long-term effects.

Pro tip: Mention that a 15% height reduction might have non-linear effects, so consider testing multiple variations (e.g., 5%, 10%, 15%) to find the optimal size. Also, highlight the need to segment by user demographics and device type.

1. Clarify the change and hypothesis

Define what 'post card' refers to (e.g., a feed card) and the exact change (height reduced by 15%). Formulate a hypothesis about the expected impact on user experience and engagement.

2. Define metrics

Identify primary metrics (e.g., click-through rate, time spent, likes/comments) and secondary/guardrail metrics (e.g., scroll depth, bounce rate, user satisfaction). Consider both short-term and long-term effects.

3. Design the experiment

Set up an A/B test with a control group (original height) and treatment group (reduced height). Ensure proper randomization, sample size calculation, and duration to capture novelty effects.

4. Analyze results

Use statistical tests to compare metrics between groups. Check for significance, effect size, and segment-level differences. Investigate qualitative feedback if available.

5. Interpret and decide

Weigh trade-offs between engagement gains and potential UX degradation. Recommend whether to roll out, iterate, or abandon based on overall impact and business goals.

Key Points to Mention

  • A/B testing methodology and statistical significance
  • Selection of appropriate engagement metrics (e.g., CTR, dwell time)
  • Guardrail metrics to monitor unintended consequences
  • Segmentation analysis (e.g., by device, user demographics)
  • Consideration of long-term effects and novelty bias
  • Qualitative user feedback and UX principles

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

Q2

After launching the card redesign, U.S. revenue increased but Thailand revenue dropped. What do you investigate and what do you do next?

Root Cause AnalysisPricing & MonetizationProduct Analytics & Metrics
Author's notes

This one is sneaky because your first instinct is to just say 'segment the data' and call it a day.

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AI HintsAI Generated

Suggested Approach

Start by validating the data and confirming the revenue drop in Thailand is real and not due to tracking or seasonality. Then segment the analysis by user cohorts, card types, and transaction behavior to isolate the cause, and finally propose targeted experiments or fixes based on the root cause.

Pro tip: Always consider local market nuances—Thailand may have different payment habits, regulatory constraints, or competitive dynamics that make the redesign less effective. Demonstrating awareness of these factors shows you think globally and avoid assuming U.S. success translates everywhere.

1. Validate the data

Check for data pipeline issues, tracking errors, or seasonality that could explain the drop. Confirm the revenue decline is statistically significant and not due to random variation.

2. Segment the impact

Break down Thailand revenue by user demographics, card types, transaction channels, and new vs. existing users to identify which segments are driving the drop.

3. Compare with U.S. and control groups

Analyze differences between U.S. and Thailand markets, including user behavior, payment methods, and competitive landscape. Use A/B testing or holdout groups to isolate the redesign's effect.

4. Identify root cause

Investigate potential causes such as usability issues, cultural misalignment, pricing changes, or technical problems specific to Thailand. Gather qualitative feedback and session recordings if available.

5. Recommend and act

Propose targeted fixes or experiments (e.g., localized redesign, rollback for Thailand) and define success metrics. Prioritize based on impact and effort, and monitor closely.

Key Points to Mention

  • Data validation and statistical significance testing
  • Segmentation by user cohorts, card types, and transaction behavior
  • Local market factors: payment preferences, regulations, competition
  • A/B testing or holdout groups to isolate the redesign's impact
  • Root cause analysis techniques (e.g., 5 Whys, funnel analysis)
  • Actionable next steps: localized experiments, rollback, or iterative improvements

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