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Meta·Data Scientist·Technical Phone Screen·Senior

Senior
Jul 2026

Summary

Meta data scientist interview with a meaty statistics and product analytics question about fake news. Nothing behavioral, just one big open-ended design problem that spiraled in a few directions I wasn't fully ready for.

Questions Asked (1)

Q1

How would you design a sampling strategy to estimate the proportion of fake news on the platform, including confidence intervals? And which user interaction metrics would you use to measure its impact?

A/B Testing & ExperimentationProduct Analytics & MetricsRoot Cause Analysis
Author's notes

The sampling design part I handled okay.

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AI HintsAI Generated

Suggested Approach

Start by defining the target population and sampling frame, then choose a probability sampling method (e.g., stratified random sampling) to estimate the proportion of fake news with a desired confidence interval. Next, outline how to compute the sample size and confidence intervals, and finally discuss user interaction metrics (e.g., engagement, shares, reports) to measure the impact of fake news and potential interventions.

Pro tip: Emphasize the trade-off between sample size and cost, and mention that stratification by content type or user demographics can improve precision. Also, note that fake news detection may require human labeling, so incorporate a plan for quality control and inter-rater reliability.

1. Define the target population and sampling frame

Clarify what constitutes 'fake news' and identify the population of posts or users. Determine the sampling frame (e.g., all public posts in a given period) and any stratification variables (e.g., content category, user region).

2. Choose a sampling design

Select a probability sampling method such as stratified random sampling or cluster sampling to ensure representativeness. Discuss how to allocate sample sizes across strata and handle potential non-response or missing data.

3. Determine sample size and compute confidence intervals

Calculate the required sample size based on desired margin of error and confidence level (e.g., 95% CI). Use formulas for proportions (e.g., n = Z^2 * p*(1-p) / E^2) and adjust for design effects. Explain how to compute the confidence interval for the estimated proportion.

4. Measure impact using user interaction metrics

Identify key metrics such as engagement rate (likes, comments, shares), click-through rates, report rate, and time spent. Compare these metrics between fake news and non-fake news content, and assess how interventions (e.g., labeling) affect them.

5. Validate and iterate

Discuss validation of the sampling strategy (e.g., comparing with ground truth) and potential biases. Suggest iterative refinement based on initial findings and A/B testing for interventions.

Key Points to Mention

  • Probability sampling methods (e.g., stratified random sampling) to ensure representativeness
  • Sample size calculation for estimating proportions with desired confidence level and margin of error
  • Confidence interval computation and interpretation (e.g., Wilson score interval for proportions)
  • Stratification by content type, user demographics, or engagement levels to improve precision
  • User interaction metrics: engagement rate, shares, comments, reports, and time spent
  • Potential biases (e.g., selection bias, labeling bias) and mitigation strategies

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