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Meta·Data Scientist·Technical Phone Screen·Intermediate

Intermediate
Apr 2026

Summary

Meta DS interview focused entirely on a local SMB ads product case. Three questions, all connected to the same scenario, which made it feel more like a product sense loop than a traditional DS screen.

Questions Asked (3)

Q1

How would you define a 'local business' for the purpose of Facebook ads targeting?

Product Sense & IdeationProduct Analytics & Metrics
Author's notes

I started rattling off things like physical storefront, zip code radius, employee headcount.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the business objective behind defining 'local business' for Facebook ads targeting, then propose a data-driven definition that balances precision and recall based on available signals. Structure your answer around how you would operationalize the definition, measure its impact, and iterate using A/B tests.

Pro tip: Acknowledge that 'local business' is a fuzzy concept and that the optimal definition depends on the advertiser's goal (e.g., driving foot traffic vs. online sales), so you would build a flexible, multi-tiered definition rather than a one-size-fits-all rule.

1. Clarify the objective

Ask what problem we're solving: is it to help small local businesses reach nearby customers, or to help national brands target local audiences? The definition should align with the product goal.

2. Identify available signals

List data points such as business address, service radius, page category, check-ins, and user interactions. Consider both explicit (e.g., claimed address) and implicit (e.g., user engagement patterns) signals.

3. Propose a multi-tiered definition

Define tiers: e.g., Tier 1: businesses with a physical location and a service radius; Tier 2: online-only businesses serving a local area; Tier 3: businesses with local intent but no clear radius. Use thresholds based on data distributions.

4. Validate and measure

Use metrics like precision/recall against a labeled set, or run A/B tests to see how the definition affects ad performance (e.g., CTR, conversion rate, local reach).

5. Iterate and refine

Continuously update the definition based on feedback, new data, and changing business needs. Consider edge cases and ensure scalability.

Key Points to Mention

  • Business address and service radius as primary signals
  • User engagement patterns (e.g., check-ins, local searches) as implicit signals
  • Trade-off between precision and recall in defining local businesses
  • Impact on ad targeting: relevance, reach, and cost
  • Need for a flexible definition that can adapt to different advertiser goals
  • Use of A/B testing and metrics like local conversion rate to evaluate the definition

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

Q2

If small businesses are boosting their popular posts, what metric would you use to measure whether that's actually working?

Product Analytics & MetricsPricing & Monetization
Author's notes

Went straight to CTR and then corrected myself mid-sentence, which was awkward.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the goal of boosting popular posts—likely to increase reach, engagement, or conversions for small businesses. Then propose a primary metric that directly measures success (e.g., incremental engagement or ROI) and support it with guardrail metrics to ensure no negative side effects. Finally, outline how you would measure incrementality (e.g., A/B test or causal inference) to attribute the boost's impact.

Pro tip: Emphasize incrementality: the boost's true value is the lift over what would have happened organically. Mention that you'd use a holdout group or synthetic control to isolate the causal effect, which shows rigor and avoids common attribution pitfalls.

1. Clarify the objective

Ask what 'working' means: is the goal to increase reach, engagement, conversions, or revenue for small businesses? Align the metric with the business objective.

2. Choose a primary success metric

Select a metric that directly reflects the objective, such as incremental engagement rate, click-through rate, or return on ad spend (ROAS) for boosted posts.

3. Define guardrail metrics

Identify metrics to monitor for unintended consequences, such as organic reach decline, user experience (e.g., hide/report rates), or cost per acquisition.

4. Design measurement approach

Propose an experiment (e.g., A/B test with holdout) or quasi-experimental method (e.g., difference-in-differences) to measure incremental lift and attribute causality.

5. Consider long-term and segment-level effects

Discuss how to measure sustained impact over time and across different small business segments, ensuring the metric is robust and not gamed.

Key Points to Mention

  • Incremental lift vs. organic performance (causal inference)
  • Primary metric aligned with business goal (e.g., ROAS, engagement rate)
  • Guardrail metrics to detect negative side effects (e.g., user experience, organic reach cannibalization)
  • A/B testing or holdout methodology for accurate attribution
  • Segment analysis by business type, industry, or size
  • Long-term retention or repeat boost behavior as a proxy for sustained value

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

Q3

You're running an experiment and CTR on boosted posts comes back lower than expected. Walk through your hypotheses and how you'd validate them.

A/B Testing & ExperimentationRoot Cause Analysis
Author's notes

This was the most fun part.

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AI HintsAI Generated

Suggested Approach

Start by acknowledging that a lower-than-expected CTR could stem from various sources, and structure your answer by categorizing hypotheses into data quality, experiment design, and user behavior. Then, for each category, propose specific validation methods such as data audits, AA tests, and segment analyses to isolate the root cause.

Pro tip: Always check for Sample Ratio Mismatch (SRM) first—it's a common and easily detectable issue that can invalidate results. Also, consider that boosted posts might suffer from ad fatigue or audience saturation, so look beyond the immediate experiment metrics.

1. Verify Data Quality and Experiment Integrity

Check for data pipeline issues, logging errors, and SRM to ensure the experiment was run correctly. Validate that the control and treatment groups are comparable and that the CTR metric is calculated accurately.

2. Examine Experiment Design and Implementation

Review the experiment setup for potential flaws such as incorrect randomization, contamination between groups, or misconfigured boost delivery. Ensure that the boost was actually applied as intended and that there are no technical glitches.

3. Analyze User Behavior and Segment Differences

Break down CTR by user segments (demographics, device, geography, etc.) to see if the drop is concentrated in specific groups. Consider behavioral factors like ad fatigue, novelty effects, or changes in user engagement over time.

4. Consider External and Contextual Factors

Investigate if external events (e.g., holidays, news, competitor actions) or platform changes (e.g., algorithm updates) could have impacted CTR. Also, assess whether the boost altered the audience composition or ad placement in unexpected ways.

5. Validate Hypotheses with Targeted Tests

Design follow-up experiments or analyses to test each hypothesis, such as AA tests, holdout groups, or deep dives into user logs. Use statistical methods to confirm whether observed differences are significant and actionable.

Key Points to Mention

  • Sample Ratio Mismatch (SRM) check
  • Data quality audits (logging, pipeline)
  • Segment analysis (e.g., by demographics, device, geography)
  • Ad fatigue and novelty effects
  • Experiment design flaws (randomization, contamination)
  • External factors (seasonality, platform changes)

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