A/B Testing Interview Questions
A/B testing questions are central to data science and product analytics interviews at companies like Meta, Google, Netflix, and Airbnb.
Expect questions on experiment design, randomization units, sample size calculation, multiple comparisons, and metric selection.
Interviewers evaluate your statistical rigor, practical judgment, and ability to communicate experiment results.
Common A/B testing interview patterns
- Designing an experiment for a product change
- Calculating sample size and experiment duration
- Choosing between one-sided and two-sided tests
- Handling multiple comparisons and peeking
- Interpreting results with novelty or primacy effects
- Network effects and interference between test groups
A/B testing interview questions
Design A/B Test for Google Maps UI Change
Design Experiment to Test New Hashtag Recommender Algorithm
Leverage Data Sources for Effective Push Notification Strategy
Extract insights from a multi-entry funnel scorecard
Reduce variance with covariate adjustment
Diagnose Sudden Drop in Credit-Card Approval Rate
Analyze private-account product metrics
Evaluate Facebook's Restaurant Recommendations Feature Effectiveness
Investigate MAU Drop and Test Coupons
Recommend and validate a budget allocation strategy
Detect and quantify wash trading
Test 15s to 60s video length change
Diagnose March Uber ride-volume drop
How would you grow Meta products?
Analyze homepage drop and feed ranking
Design an experiment to measure latency impact
Define and validate an airline profitability metric
Diagnose a sudden metric spike or drop
Design analytics and experiment for group video calls
Common mistakes in A/B testing interviews
- Not specifying the randomization unit (user vs session vs page)
- Peeking at results before reaching the required sample size
- Ignoring practical significance when statistical significance is achieved
- Not considering guardrail metrics
- Failing to account for novelty effects in short experiments
How A/B testing questions are evaluated
Structure your experiment design: hypothesis, metrics, unit, sample size, duration.
Discuss what could go wrong and how you would detect it.
Show ability to make a recommendation even when results are ambiguous.
Related analytics concepts
A/B Testing Interview FAQs
How do you determine the sample size for an A/B test?
Use a power analysis with inputs: baseline metric, minimum detectable effect (MDE), significance level (alpha, usually 0.05), and power (usually 0.80). Larger effects need fewer samples. For small MDE on rare events, you may need millions of users.
What is the difference between statistical and practical significance?
Statistical significance means the observed difference is unlikely due to chance (p-value < alpha). Practical significance means the effect is large enough to matter for the business. A statistically significant 0.01% lift may not be worth the engineering cost to ship.